Allows users to check arbitrary objects against React prop types without
relying on the implementation details of the prop validators themselves.
An example of why this is important: some prop validators may throw,
while others return an error object. Calling a prop validator manually
requires handling both cases. `checkPropTypes` does this for you.
ReactPropTypeLocationNames was a map of location identifiers to location
display names, for use in warnings. But in practice, this did nothing
except rename "childContext" to "child context." Not worth it, IMO.
Since we are going to add an API for running prop type checks manually,
we need the ability to support arbitrary prop type locations. So
each place that used to accept a ReactPropTypeLocation now just accepts
a string.
> This PR adds a test (initially failing) for this case along with a fix for stack and fiber. The stack fix was copied from a Diff submitted by @sema. The fiber fix just required us to stop leaking properties for unmounted views.
> Longer term we may want to explicitly invoke a release event listener for a responder just before unmounting it. This PR does not do that.
Due to how Jest and other mocking libraries work in userland, modules that are required might not be referentially equal at various stages of the application lifecycle. This isnt a perfect fix, but by having the require calls inline, it has a better liklihood of ensuring emptyObject is the same reference
ReactStatelessComponent-test.js fails due to warnings not showing up when functional components mount or update. This PR ports the existing warnings from stack and re-applies them to fiber functional components and attempts to re-use some logic in ReactFiberContext that currently exists for showing warnings when dealing with class components.
...without dropping the update. This won't work the other way around,
if you assign to this.state before calling setState. we'll add a
deprecation warning so people stop relying on this pattern.
* Improved for a better understanding
that code shouldn't name this parameter onchange. It is so confusing for a starter of ReactJs like me. It looks like that the onChange is an common event from props.
* Update the lifting state up paragraph
I tried to write something to explain to starter programmers in react, how we lift the state up calling a method defined by the ancestor and called by the children that will affect the children element.
* Rewrite Lifting State Up
Now we won't add closures unnecessarily. I verified that we have no code that throws -- adding some then running `grunt build:modules` correctly throws.
In React Native events can fire on text nodes (on Android at least).
In that case, the current element will be a string and not props. These
can not have event handlers on them so we need to bail out so that
we don't throw later on.
Test Plan: Couldn't figure out how to write a unit test. :\ Verified that enter/leave bubbling now works correctly in one FB interface that was broken though.
This is currently used by both isomorphic and the renderer. I think that
we can probably split these up. The isomorphic type should actually be
different. It has to do with that the caller needs to know exactly which
type of element it is but this is never needed in the renderer which only
needs to know that the type is internally consistent.
The owner type is renderer dependent so it can literally be anything.
This delays the type check until the point when the engine will have to
perform a type check regardless.
Because the error is now thrown during the commit phase rather than
when the callback is originally scheduled, we warn in DEV when
scheduling so it's easier to track down.
Flow maybe types accept both null and undefined. When the final
parameter of a function accepts a maybe type, passing nothing
(undefined) successfully typechecks, which can lead to bugs if the
omission is accidental. Being forced to pass null is harder to screw up.
Explicit null checks are also faster.
Previously, calls to validateCallback() with a null callback value resulted in runtime errors if a certain transform was not applied prior to running. This commit wraps the invariant() with the condition check so as to avoid calling formatUnexpectedArgument() unless necessary. It also replaces the truthy/falsy callback check with an explicit check for improved performance.
* Add toTree() method to stack and fiber TestRenderer
* Address PR feedback
* Refactor TestRenderer to use correct root
* Rebase off master and fix root node references
* Add flow types
* Add test for null rendering components
* Remove last remaining lint error
* Add missing test
These mocks are things we expect to be available in the React Native
environment. I'd like to move them out of the renderer folder so that we
can sync that folder to React Native as is without overriding its mocks.
I motivate by the fact that they're not really part of the renderer code
itself. I leave the ReactNative mock since that is in fact part of the
renderer.
* Fixed ReactNativeFiber event system regression introduced in b354db2
Also added test coverage to ReactNativeEvents-test for Fiber
* ReactNative tests now run against fiber renderer when env flag set
Updated the test-framework-setup file so that record-tests runs native tests against ReactNativeFiber. ReactComponentTreeHook native tests all now fail but that's expected.
* Avoid calling setChildren() if no children
Submitted this internally already.
Needed because people import this file directly and they might not have the renderer inject the findNodeHandle handler yet.
We have a bunch of tests that are meant to test generic React behavior.
However, we've written the tests against the DOM renderer. This moves
tests that depend on ReactDOM or ReactTestUtils out of the shared repo.
This will let us sync the shared repo directly to environments that don't
support running these tests. Such as React Native.
* Revert "Revert "Warn if PropType function is called manually (#7132)""
This reverts commit be71f76ed8b7dbad25e3519455605252d3daf683.
In other words, now we again have the warning if you attempt to call PropTypes manually.
It was removed in #8066 but we shouldn't have done this since we still want to avoid people accidentally calling them in production (and even more so since now it would throw).
Fixes#8080.
* Pass secret in ReactControlledValuePropTypes
* Record tests
The entries of a map are a two-element array of [key, value], which
React will treat as fragments with children. This is unlikely to ever
be the intended behavior, so we warn.
It is strange to get a handle on the Fiber since it is one of possibly two
root Fibers. The correct way to get the current Fiber is through the
root.current.
I exposed the Fiber originally because I thought we might use it for
Portals but we went with a different approach. So we don't need this.
* Add note about refs on stateless components
* Move info about refs in the stateless components to the main section
* Simplification of the part about refs and functional components
* Tweaks
* Move sections around
* Oops
* Rearrange more sections
* Add onToggle event to details tag
Fixes#8761
* Map onToggle event on ReactDOMFiberComponent
* Tweak doc
* Trap events on setInitialProperties for details tag
The production error code system depends on the exact template string
that is passed to `invariant`. This changes the Fiber templates to
match the Stack ones.
* Explain arbitrariness of ref name in callback
The sample code was confusing because it's not clear that "textInput" in this.textInput is an arbitrary name for the ref.
* Tweak wording
* 'beginLifeCycleTimer' function of ReactDebugTool.js
* 'bindAutoBindMethod' function of ReactClass.js
* 'warnNoop' function of ReactServerUpdateQueue.js
* 'getInternalInstanceReadyForUpdate' function of ReactUpdateQueue.js
* 'warnNoop' function of ReactNoopUpdateQueue.js
* 'getDeclarationErrorAddendum' function of ReactDOMComponent.js
* 'getSourceInfoErrorAddendum' function of ReactElementValidator.js
* 'getDeclarationErrorAddendum' function of instantiateReactComponent.js and ReactElementValidator.js
* 'traverseAllChildrenImpl' function of traverseAllChildren.js
* 'attachRef' function of ReactRef.js
* 'mountIndeterminateComponent' function of ReactFiberBeginWork.js
* 'createFiberFromElementType' function of ReactFiber.js
* 'getDeclarationErrorAddendum' function of ReactDOMSelect.js
* 'unmountComponentAtNode' function of ReactMount.js
* 'getDeclarationErrorAddendum' function of ReactControlledValuePropTypes.js
* 'checkRenderMessage' function of CSSPropertyOperations.js
* 'getDeclarationErrorAddendum' function of ReactDomFiberSelect.js
* 'getCurrentComponentErrorInfo' function in 'ReactElementValidator'
* 'getDeclarationErrorAddendum' function in ReactDOMFiberComponent.js
* Initial React DevTools support for Fiber
* Record a newly failing irrelevant test
This is fine because we don't use it in Stack anyway (at least not that part), and we also rely on Set/Map in other parts of code.
The newly failing test is the one saying "it works without Map/Set".
* Explicitly check for Fiber DevTools support
This lets us ignore pre-Fiber DevTools instead of crashing them by injecting a different API.
* Track the roots in DevTools instead
* Lol Dan this is not how warnings work in our codebase
* Move injection to the renderer
* Notify DevTools about unmounts
* Make it work in production
* Fix lint and flow
* Fixups
* Address feedback
When visiting the yields, the root is the stateNode of the coroutine. If
its return value is wrong we'll end up at the alternate of the
workInProgress which will start scanning its children which is wrong.
There are a few different issues:
* Updates result in unnecessary duplicate placements because it can't find the current fiber for continuations.
* When run together, coroutine update and unmounting tests appear to lock down in an infinite loop. They don't freeze in isolation.
I don't have a solution for this but just leaving it for future fixes.
Coroutines was kind of broken because it tried to do reparenting and
enabling state preservation to be passed along the coroutine. However,
since we couldn't determine which Fiber was "current" on a reified yield
this was kind of broken.
This removes the "continuation" part of yields so they're basically just
return values. It is still possible to do continuations by just passing
simple functions or classes as part of the return value but they're not
stateful.
This means that we won't have reparenting, but I actually don't think we
need it. There's another way to structure this by doing all the state in
the first phase and then yielding a stateless representation of the result.
This stateless representation of the tree can then be rendered in different
(or even multiple) locations.
Because we no longer have a stateful continuation, you may have noticed
that this really no longer represent the "coroutine" concept. I will
rename it in a follow up commit.
It is slightly more useful this way because when we want to find host nodes
we typically want to do so in the second phase. That's the real tree where
as the first phase is more of a virtual part of the tree.
* Add benchmarking tutorial
I've written what I hope is the simplest introduction to benchmarking React components. It's meant to be straightforward and easy to follow for beginners. If you agree that it would be helpful, I'd like to add it to the docs.
Would also welcome any and all feedback.
* Just put links together
* Reminder: strip quotes from attributes with JS code
Web developers who are used to standards-compliant HTML and XML will, out of habit, put quotes around all attributes because the standards require them. Other templating systems like ASP.NET also require (or at least allow) quotes around attributes that contain code. This behavior will get users into trouble in JSX because a quoted attribute is always treated as a string literal, even if it contains curly-braced javascript code. Let's add to the docs to help newbies evade this problem.
* Tweak wording
I introduce the ReactDOMFrameScheduling module which just exposes
rIC and rAF.
The polyfill works by scheduling a requestAnimationFrame, store the time
for the start of the frame, then schedule a postMessage which gets
scheduled after paint. The deadline is set to time + frame rate.
By separating the idle call into a separate event tick we ensure that
layout, paint and other browser work is counted against the available time.
The frame rate is dynamically adjusted by tracking the minimum time between
two rAF callbacks. This is not perfect because browsers can schedule
multiple callbacks to catch up after a long frame. To compensate for this
we only adjust if two consecutive periods are faster than normal.
This seems to guarantee that we will hit frame deadlines and we don't end
up dropping frames. However, there is still some lost time so we risk
starving by not having enough idle time.
Especially Firefox seems to have issues keeping up on the triangle demo
However, that is also true for native rIC in Firefox. It seems like more
render work is scheduled on the main thread pipeline and also that JS
execution just generally has more overhead.
It's not just events that read the current props. Controlled components
do as well. Since we're no longer updating the Fiber pointer during updates
we have to instead read from the node props to get the current props.
Since this method is no longer just used for events I renamed it.
* Allow renderers to return an update payload in prepareUpdate
This then gets stored on updateQueue so that the renderer doesn't need to
think about how to store this.
It then gets passed into commitUpdate during the commit phase.
This allows renderers to do the diffing during the time sliced path,
allocate a queue for changes and do only the absolute minimal work to
apply those changes in the commit phase.
If refs update we still schedule and update.
* Hack around the listener problem
* Diff ReactDOMFiber properties in prepareUpdate
We now take advantage of the new capability to diff properties early.
We do this by generating an update payload in the form of an array with
each property name and value that we're about to update.
* Add todo for handling wasCustomComponentTag
* Always force an update to wrapper components
Wrapper components have custom logic that gets applied at the commit phase
so we always need to ensure that we schedule an update for them.
* Remove rootContainerInstance from commitMount
No use case yet and I removed it from commitUpdate earlier.
* Use update signal object in test renderer
* Incorporate 8652 into new algorithm
* Fix comment
* Add failing test for flipping event handlers
This illustrates the problem that happens if we store a pointer to the
Fiber and then choose not to update that pointer when no properties change.
That causes an old Fiber to be retained on the DOM node. Then that Fiber
can be reused by the pooling mechanism which then will mutate that Fiber
with new event handlers, which makes them active before commit.
* Store current props in the RN instance cache and on the DOM node
This represents the current set of event listeners. By not relying on the
Fiber, it allows us to avoid doing any effects in the commit phase when
nothing changes.
This is a bit ugly. Not super happy how this all came together.
* use an easier word
The word `mandatory` is relatively difficult for people with ESL (English as a second language), so I propose an alternative word.
This would be much easier to understand.
* use simpler word
* FiberDebugger uses packages built in local
* Fix key warnings in FiberDebugger
* Remove react packages from package.json and yarn.lock for using pacakges built in local
* Remove fiber.js from `files` in package.json
* Add a test for rendering SVG into a non-React SVG tree
It is failing in Fiber.
* Add a test for rendering HTML into non-React foreignObject
It happens to pass in Fiber.
* Determine root namespace by container namespace, not just tag
A tag alone is not enough to determine the tree namespace.
* Skip the test that exhibits jsdom bug in non-createElement mode
jsdom doesn't give HTML namespace to foreignObject.innerHTML children.
This problem doesn't exist in the browsers.
https://github.com/facebook/react/pull/8638#issuecomment-269349642
We will skip this test in non-createElement mode considering
that non-createElement mounting is effectively dead code now anyway.
A new module has been added (ReactFiberErrorLogger). This logs error information (call stack and component stack) to the console to make errors easier to debug. It also prompts users to use error boundaries if they are not already using them.
In the future, perhaps this will be injectable, enabling users to provide their own handler for custom processing/logging. For the time being, this should help with issues like this / #2461.
Previous (probably unintentional) behavior of Stack was to allow components to define childContextTypes without also supplying a getChildContext property. This PR updates Fiber to (temporarily) mimic that behavior. It also adds warning messages to both Fiber and Stack (along with a test).
For the time being, Fiber components with a missing getChildContext method will return the parent context as-is, after warning.
Fixes the case where there's an uncaught error and the root unmounts.
We implement this by rendering the root as if its child is null. Null is
not usually allowed at the top level, so we need to special case it.
Currently we update the memoized inputs (props, state) during the
complete phase, as we go back up the tree. That means we can't reuse
work until of its children have completed.
By moving memoization to the begin phase, we can do a shallow bailout,
reusing a unit of work even if there's still work to do in its children.
Memoization now happens whenever a fiber's `child` property is updated;
typically, right after reconciling. It's also updated when
`shouldComponentUpdate` returns false, because that indicates that the
given state and props are equal to the memoized state and props.
* fix failed tests on Windows #8737
* Use regexp literal instead of `RegExp` constructor so that we don't need to bother with escaping special character like `\` and `.`.
Note that by removing the path separator in regexp, I've relaxed the matching condition a little.Since there's little chance we have files like `XXXReact.d.ts`,it should not matter.
We have an invariant that checks the same case right afterwards.
The warning was originally added in #5884 with a distinct wording.
However it was later changed to the same wording as the invariant in #6008.
I don't see why we would want to have both since they're saying the same thing and with (almost) the same internal stack.
This test is identical to "should warn when stateless component returns array" earlier.
It was moved from another file in #5884 so it likely survived by accident.
* ReactTestRenderer move current impl to stack dir
* ReactTestRenderer on fiber: commence!
* ReactTestRenderer: most non-ref/non-public-instance tests are passing
* Move ReactTestFiberComponent functions from Renderer to Component file
* test renderer: get rid of private root containers and root Maps
* TestRenderer: switch impl based on ReactDOMFeatureFlag.useFiber
* ReactTestRenderer: inline component creation
* ReactTestRenderer: return to pristine original glory (+ Fiber for error order difference)
* TestRendererFiber: use a simple class as TestComponentInstances
* Add `getPublicInstance` to support TestRenderer `createNodeMock`
* Rename files to end. Update for `mountContainer->createContainer` change
* test renderer return same object to prevent unnecessary context pushing/popping
* Fiber HostConfig add getPublicInstance. This should be the identity fn everywhere except the test renderer
* appease flow
* Initial cleanup from sleepy work
* unstable_batchedUpdates
* Stack test renderer: cache nodeMock to not call on unmount
* add public instance type parameter to the reconciler
* test renderer: set _nodeMock when mounted
* More cleanup
* Add test cases for root fragments and (maybe?) root text nodes
* Fix the npm package build
Explicitly require the Stack version by default.
Add a separate entry point for Fiber.
We don't add fiber.js to the package yet since it's considered internal until React 16.
* Relax the ref type from Object to mixed
This seems like the most straightforward way to support getPublicInstance for test renderer.
* Remove accidental newline
* test renderer: unify TestComponent and TestContainer, handle root updates
* Remove string/number serialization attempts since Fiber ensures all textInstances are strings
* Return full fragments in toJSON
* Test Renderer remove TestComponent instances for simple objects
* Update babylon for exact object type syntax
* Use $$typeof because clarity > punching ducks.
* Minor Flow annotation tweaks
* Tweak style, types, and naming
* Fix typo
* Update refs-and-the-dom.md
I want to propose some changes to the Refs and the DOM documentation page.
- Make it clear that string refs are legacy. It seems that this information got lost during the transition to new docs and only some part stayed the same, which was confusing when first reading the docs.
- Clarify and explain that during render, if the ref callback is provided, it will get called twice, first with `null` and then with the rendered DOM element. Discussed in https://github.com/facebook/react/issues/4533 and first proposed docs change in PR #8333.
I've also planned on adding an example for passing the refs up the component chain based on something I've needed to solve myself (e.g. you want to connect two dynamic components by line in React, so you need to both use refs and propagate them up the chain), and while it would be great to read up on this in the docs, it may be too specific for this section; I'd be happy to hear any recommendations.
* Adds more specific information about the callback
* Moved the ref callback description to the Caveats section
* Fixed suggested nits
* Replace 'each render pass' with 'updates'
* Tweak the wording
* Verify that functional component ref warning is deduplicated
It's not a big problem for string refs because the ref stays the same and the warning code path runs once per mount.
However, it is super annoying for functional refs since they're often written as arrows, and thus the warning fires for every render.
Both tests are currently failing since we're mounting twice, so even the string ref case prints warnings twice.
* Extract the warning condition to the top level
We don't want to run getStackAddendumByID() unless we actually know we're going to print the warning.
This doesn't affect correctness. Just a performance fix.
* Deduplicate warnings about refs on functional components
This fixes the duplicate warnings and adds an additional test for corner cases.
Our goal is to print one warning per one offending call site, when possible.
We try to use the element source for deduplication first because it gives us the exact JSX call site location.
If the element source is not available, we try to use the owner name for deduplication.
If even owner name is unavailable, we try to use the functional component unique identifier for deduplication so that at least the warning is seen once per mounted component.
* Fiber: warn for refs on SFCs
* Stateless refs: update warning to use component stack
* Warn for function refs (stack and fiber)
* Add owner reference to ref warnings
* Centralize stack ref warnings in ReactRef.attachRef
* Fiber stateless comp ref warning should only do work when necessary
* ReactDebugCurrentFiber maybe FunctionalComponents should act this way instead
* (chore) scripts/fiber/record-tests
* Add component._compositeType to ReactInstance Flow definition
* Don't handle 'stack inside fiber' case in the warning
We don't have a test for it. It's easy to mess it up and print the wrong thing so instead of verifying it I'll just remove this bit.
* Revert the change to getCurrentFiberOwnerName
This happened to work, but it is just a coincidence. This change didn’t really match what the function was supposed to be doing.
I’m not sure what the correct fix would be yet so this commit breaks tests.
* Add component indirection to the tests using owner name
This passes in Stack. It helps ensure we supply the correct owner name.
* Invalid type invariant should read owner from element
This brings the Fiber behavior in line with how Stack does it. The Fiber test was passing accidentally but broke down in more complicated cases (such as when we have an <Indirection> between the owner and the failing element).
Now we can also remove the weird cases from getCurrentFiberOwnerName() that didn't really make sense but helped get the (incomplete) tests pass in the past.
* Fiber should throw on a string ref inside functional component
Only store cached masked/unmasked contexts on context consumers. Move all references to __reactInternal* cached attributes inside of ReactFiberContext.
* Show Source Error Addemden if __source available
* Add Parent Stack on invalid element type
* refactor to use normalizeCodeLocInfo
* Remove ( ) from addendum
This moves the current fixture architecture to one based around create-react-app. There are a few important things to note:
* The react-loader.js script is always loaded before the bundle and will populate React and ReactDOM on the window. It is then read from the window by all components.
* The UI for the "React Sandbox" or "React Fixtures App" is also rendered with whatever version of React the user has selected. This means we dont have to deal with iframes or worry about multiple versions of React potentially interferring. But it also means that all components must be written using createClass to be fully backwards compatable. I tested back to 0.13.1 and it works fine.
This will publish all packages in build/packages/*.tgz to the "next" tag. If the current version is "stable" (doesn't trigger semver.prerelease()) then it will also update the "latest" dist-tag to point at that version.
* Add manual build fixtures
* Inject ReactDOM into ReactWithAddons from ReactWithAddons
We used to read ReactDOM as a global inside ReactAddonsDOMDependenciesUMDShim.
This didn't work in AMD environments such as RequireJS and SystemJS.
Instead, I changed it so that ReactDOM gets injected into ReactWithAddons by ReactDOM itself.
This way we don't have to try to require it (which wouldn't work because AMD doesn't handle circular dependencies well).
This means you have to load ReactDOM first before using ReactDOM-dependent addons, but this was already the case before.
This commit makes all build fixtures pass.
* Memoize ReactDOM to avoid going into require on every access
* Add Brunch fixture
* Inline requires to work around Brunch bug
See #8556 and https://github.com/brunch/brunch/issues/1591#issuecomment-270742503 for context.
This appears to be a Brunch bug but we can keep a temporary fix until the next major.
* Fix typo in Proposing a Change section in how-to-contribute.md
Not sure if it was actually intended or was a typo but changed 'If you intend to change to the public API' --> 'If you intend to make a change to the public API'
* Simplify
* Component Lifecycle In Depth documentation
* first steps to improve react component reference
* improved react component reference
- remove the component-lifecycle-in-depth
* add a note for usage of ReactDOM.findDOMNode
* one note on componentWillReceiveProps
* remove old useless images for lifecycle docs
* Tweak wording
Moved ReactFiberClassComponent validateCallback() helper function into a standalone util used by both fiber and stack implementations. Validation now happens in ReactFiberUpdateQueue so that non-DOM renderers will also benefit from it.
Reverses the effect of batchedUpdates by resetting the current
batching context.
Does not affect nested updates, which are always deferred regardless
of whether they are inside a batch.
The DOM renderer assumes that resetAfterCommit is called after
prepareForCommit without any nested commits in between. That may not
be the case now that syncUpdates forces a nested update.
To address, this changes the type of prepareForCommit to return a value
which is later passed to resetAfterCommit.
Typically, a sync update is downgraded to Task priority if it's
scheduled within another batch of work, e.g. within a lifecycle like
componentDidMount. But syncUpdates should force sync updates to not
be downgraded to Task. This will cause performWork to be
called recursively.
Currently we assume that performWork is never called recursively.
Ideally that is the case. We shouldn't rely on recursion anywhere
in Fiber.
However, to support the use of syncUpdates as an opt-in to forced-
synchronous updates, we need the ability to call performWork
recursively.
At the beginning of performWork, the state of the scheduler is saved;
before exiting, that state is restored, so that the scheduler can
continue where it left off. I've decided to use local variables to stash
the previous state. We could also store them in a record and push it to
a stack, but this approach has the advantage of being isolated to
performWork.
This can only be caused by a bug in the renderer, but we should handle
it gracefully anyway.
Added a TODO to change capturedErrors and failedBoundaries so that they
are sets of instances (stateNodes) rather than fibers, to avoid having
to check the alternate. (This outside the scope of this PR.)
For legacy purposes. Only enabled in the DOM renderer. We can remove
this in a future release when we enable incremental-by-default.
This change is unobservable because syncUpdates actually schedules
Task updates when it is called from inside another batch. The correct
behavior is to recursively begin another batch of work. We will fix it
in a subsequent commit.
The finalizeInitialChildren HostConfig method now utilizes a boolean return type. Renderers can return true to indicate that custom effects should be processed at commit-time once host components have been mounted. This type of work is marked using the existing Update flag.
A new HostConfig method, commitMount, has been added as well for performing this type of work.
This change set is in support of the autoFocus prop.
* Push class context providers early
Previously we used to push them only after the instance was available. This caused issues in cases an error is thrown during componentWillMount().
In that case we never got to pushing the provider in the begin phase, but in complete phase the provider check returned true since the instance existed by that point. As a result we got mismatching context pops.
We solve the issue by making the context check independent of whether the instance actually exists. Instead we're checking the type itself.
This lets us push class context early. However there's another problem: we might not know the context value. If the instance is not yet created, we can't call getChildContext on it.
To fix this, we are introducing a way to replace current value on the stack, and a way to read the previous value. This also helps remove some branching and split the memoized from invalidated code paths.
* Add a now-passing test from #8604
Also rename another test to have a shorter name.
* Move isContextProvider() checks into push() and pop()
All uses of push() and pop() are guarded by it anyway.
This makes it more similar to how we use host context.
There is only one other place where isContextProvider() is used and that's legacy code needed for renderSubtree().
* Clarify why we read the previous context
* Use invariant instead of throwing an error
* Fix off-by-one in ReactFiberStack
* Manually keep track of the last parent context
The previous algorithm was flawed and worked by accident, as shown by the failing tests after an off-by-one was fixed.
The implementation of getPrevious() was incorrect because the context stack currently has no notion of a previous value per cursor.
Instead, we are caching the previous value directly in the ReactFiberContext in a local variable.
Additionally, we are using push() and pop() instead of adding a new replace() method.
ReactFiberStack is the new underlying stack used by ReactFiberContext and ReactFiberHostContext. The goal is to simplify the 2 context managers and to add more errors/dev-warnings when we pop unexpected.
This changeset currently causes a lot of tests to fail (as we are currently popping too many times and/or in the wrong order). I'm pushing this branch now to share with Sebastian as he is working on a related cleanup pass at beginWork.
* Add a failing test for recursion check
* Make requestIdleCallback() and requestAnimationFrame() shims async
They no longer need to be sync in tests because we already made DOM renderer sync by default.
This fixes a crash when testing incrementalness in DOM renderer itself.
* Style fix
* Fix lint
This was a bug because of the split between ClassComponent and IndeterminateComponent -- we didn't mark effects or push context when we come from an indeterminate component. Now they behave the same way.
The code is even clumsier than before but I'm pretty worried we'll screw these up in the future if we don't unify the paths.
Not many components exercise this path but Relay containers do so it's noticeable.
This is the same thing as the previous commit but with class, root and portal.
I noticed host and portal now already covers this case in their branches
since pushHostContainer is always at the top.
Since we only call bailout from within the host component branch now, we
can just move this to the branch where we already know that this is a
host component.
As part of this I noticed that we don't always push the host context so
I moved that to the beginning of the branch.
This is no longer needed. It is effectively covered by other branches
that tries to being merging the update queue which yields the same state
object as before if there is no work. That in turn bails out.
We can shortcut in the relevant paths if needed.
Now we only bail out once we've entered each branch.
This has some repetition with regard to hasContextChanged but I'm hoping
we can just get rid of all those branches at some point since they're
mostly for backwards compatibility right now.
The functional component branch is a bit special since it has sCU in it.
The class component branch actually already covers this in a bit convoluted
way.
I will next replicate this check in each other branch.
This consolidates the reset of context to one single place right before
any new work is started.
This place is burried in a bit of an awkward place but findNextUnitOfWork
happens right before any new work starts. That way we're guaranteed to have
an empty stack before we start anything new.
The benefit of this is that we don't have to rely .return being null when
entering beginWork but we also don't have to check it every time in the
hot path.
Fixes an issue (in both Stack and Fiber) where enqueueSetState causes
a synchronous update that flushes before enqueueCallback is ever called.
Now enqueueSetState et al accept an optional callback so that both
are scheduled at the same time.
Otherwise you fall into an infinite loop where root fails -> host env
throws -> root fails...
This is a worst-case scenario that should only be possible if there's
a bug in the renderer.
We warn about getInitialState() usage in class components because users may have accidentally used it instead of state. If they have also specified state though then we should skip this warning.
Context: https://twitter.com/soprano/status/810003963286163456
* (WIP) Nesting warnings
* Remove indirection
* Add a note about namespace
* Fix Flow and make host context required
This makes it easier to avoid accidental nulls.
I also added a test for the production case to avoid regressing because of __DEV__ branches.
We should be able to support passing a function to replaceState, which
receives the accumulation of all the previously applied state updates.
Which means we shouldn't drop those updates from the queue. Technically,
we could drop them only when an object is passed to replaceState, but
that seems like more trouble than it's worth.
Go back to using a flag, instead. I removed it before because I thought
we might want to get rid of the top-level UpdateQueue type and put
the fields directly on the fiber, but since we're keeping UpdateQueue
we can put hasForceUpdate on there.
The update is scheduled as if the current processing update has already
been processed; if it has the same or higher priority, it will be
flushed in the same batch.
We also print a warning.
The queue maintains a pointer to the last progressed update in the list.
Updates that come after that pointer are pending. The pointer is set to
the end of the list during reconciliation.
Pending updates are sorted by priority then insertion. Progressed
updates are sorted by the order in which they were applied during
reconciliation, which may not be by priority: if a component bails out
before the updates are committed, in the next render, the progressed
updates are applied in the same order that they were previously, even if
a higher priority update comes in.
Once a progressed update is flushed/committed, it's removed from
the queue.
We need to be able to access both, and since the list uses forward
pointers, it makes more sense to point to the one that comes first.
Otherwise to get the last progressed update you have to start at the
beginning of the list.
When resetting the priority in the complete phase, check the priority of
the update queue so that updates aren't dropped.
Updates inside render, child cWRP, etc are no longer dropped.
The next step is sort the queue by priority and only flush updates that
match the current priority level.
Restructures the update queue to maintain a pointer to the first
pending update, which solves a few problems:
- Updates that occur during the begin phase (e.g. in cWRP of a child)
aren't dropped, like they are currently. This isn't working yet because
the work priority is reset during completion. The following item will
fix it.
- Sets us up to be able to add separate priorities to each update in
the queue. I'll add this in a subsequent commit.
* Implement component stack for some warnings in Fiber
* Keep Fiber debug source up to date
When an element changes, we should copy the source and owner again.
Otherwise they can get stale since we're not reading them from the element.
* Remove outdated TODOs from tests
* Explicitly specify Fiber types to include in the stack
Fixes an accidental omission when both source and owner are null but displayName exists.
* Fix mised Stack+Fiber test to not expect extra warnings
When we're in Fiber mode we don't actually expect that warning being printed.
* Warn on passing different props to super()
* Implement duplicate key warnings
We keep known keys in a set in development. There is an annoying special case where we know we'll check it again because we break out of the loop early.
One test in the tree hook regresses to the failing state because it checks that the tree hook works without a Set available, but we started using Set in this code. It is not essential and we can clean this up later when we decide how to deal with polyfills.
* Move ReactTypeOfWork to src/shared
It needs to be available both to Fiber and Isomorphic because the tree hook lives in Isomorphic but pretty-prints Fiber stack.
* Add dev-only ReactDebugCurrentFiber for warnings
The goal is to use ReactCurrentOwner less and rely on ReactDebugCurrentFiber for warning owner name and stack.
* Make Stack invariant messages more consistent
Fiber used a helper so two tests had the same phrasing.
Stack also used a helper for most invariants but hardcoded a different phrase in one place.
I changed that invariant message to use a helper which made it consistent with what it prints in Fiber.
* Make CSSPropertyOperations use getCurrentFiberOwnerName()
This gets mount-time CSS warnings to be printed.
However update-time warnings are currently ignored because current fiber is not yet available during the commit phase.
We also regress on HostOperation hook tests but this doesn't matter because it's only used by ReactPerf and it doesn't work with Fiber yet anyway. We'll have to think more about it later.
* Set ReactDebugCurrentFiber during the commit phase
This makes it available during updates, fixing the last failing test in CSSPropertyOperations.
* Add DOM warnings by calling hooks directly
It is not clear if the old hook system is worth it in its generic incarnation. For now I am just hooking it up to the DOMFiber renderer directly.
* Add client-side counterparts for some warning tests
This helps us track which warnings are really failing in Fiber, and which ones depend on SSR.
This matches what we do in Fiber -- and doing it this way is the only way we can prepare new views in the background before unmounting old ones.
In particular, this breaks this pattern:
```js
class Child1 extends React.Component {
render() { ... }
componentWillMount() {
this.props.registerChild(this);
}
componentWillUnmount() {
this.props.unregisterChild();
}
}
class Child2 extends React.Component {
render() { ... }
componentWillMount() {
this.props.registerChild(this);
}
componentWillUnmount() {
this.props.unregisterChild();
}
}
class Parent extends React.Component {
render() {
return (
showChild1 ?
<Child1
registerChild={(child) => this.registered = child}
unregisterChild={() => this.registered = null}
/> :
<Child2
registerChild={(child) => this.registered = child}
unregisterChild={() => this.registered = null}
/>
);
}
}
```
Previously, `this.registered` would always be set -- now, after a rerender, `this.registered` gets stuck at null because the old child's componentWillUnmount runs *after* the new child's componentWillMount.
A correct fix here is to use componentDidMount rather than componentWillMount. (In general, componentWillMount should not have side effects.) If Parent stored a list or set of registered children instead, there would also be no issue.
This matches the behavior in Fiber. Normally we would change Fiber
to match Stack to minimize breaking changes for the initial release.
However, in this case it would require too large a compromise to change
Fiber to act like Stack.
We introduced runtime validation of tag names because we used to generate
HTML that was supposed to be inserted into a HTML string which could've
been an XSS attack.
However, these days we use document.createElement in most cases. That
already does its internal validation in the browser which throws. We're now
double validating it. Stack still has a path where innerHTML is used and
we still need it there. However in Fiber we can remove it completely.
In #2756 we ended up using toLowerCase to allow case insensitive HTML tags.
However, this requires extra processing every time we access the tag or
at least we need to process it for mount and store it in an extra field
which wastes memory.
So instead, we can just enforce case sensitivity for HTML since this might
matter for the XML namespaces like SVG anyway.
* Remove array indirection in host context
* Keep a single context stack with a null sentinel
This lets us keep subtrees separated without maintaining independent context arrays for subtrees.
* There is always exactly one null by the time we pop a portal
I was trying to be smart but didn't need to.
* Cache current context
* Enable additional (failing) portal tests
* Fix portal unmounting
When unmount a portal, we need to unmount *its* children from itself.
This is similar to what we would do for a root if we allowed deleting roots.
* Skip portals when looking for host siblings
A portal is not part of that host tree despite being a child.
* Fix comment typo
* Add a failing test for portal child reconciliation
It is failing because portal bails out of update, seeing null in pendingProps.
It is null because we set pendingProps to nextPortal.children, which is null in this test.
* Fix the bug when switching to a null portal child
If pendingProps is null, we do a bailout in beginWork.
This prevents unmounting of the existing child when the new child is null.
We fix this by changing portal fiber's pendingProps to be the portal object itself instead of its children.
This way, it is never null, and thus doesn't cause a false positive in the bailout condition.
* Add a comment about HostPortal in getHostSibling
* Revert the fix because I don't know why it worked
unmountHostComponents() should have worked despite finding the wrong parent because it should have changed the parent when pushing and popping the portals.
* Don't call commitDeletion recursively
This leads to a "Cannot find host parent" bug because commitDeletion() clears the return field.
When we're inside the loop, we assign node.sibling.return to node.return but by this moment node.return has already been nulled.
As a solution we inline code from commitDeletion() without the nulling.
It still fails tests but for a different reason (unrelated bug).
* Skip portal children in commitNestedUnmounts()
We are currently already visiting them in commitUnmount() portal case since it's recursive.
This condition avoids visting them twice.
* Set node.child.return before going deeper
It doesn't seem to influence existing tests but we have this protection in all other similar places.
It protects against infinite loops.
* Revert "Fix the bug when switching to a null portal child"
This reverts commit ed9747deedf11455ba3eb65648007ab99c26ea58.
I'll solve this by using an array in place of null instead.
* Use [] for empty Portal pendingProps
This avoids a false positive bailout with pendingProps == null when portal is empty.
- In the previous example, the code works even without using bind(this) in the constructor.
- the reason being handleClick doesn't even use `this` and its just calling the global function alert.
- this change make use of this via access this.state.
* Test that SVG elements get created with the right namespace
* Pass root to the renderer methods
* Keep track of host instances and containers
* Keep instances instead of fibers on the stack
* Create text instances in begin phase
* Create instance before bailing on offscreen children
Otherwise, the parent gets skipped next time.
We could probably create it later but this seems simpler.
* Tweak magic numbers in incremental tests
I don't understand why they changed but probably related to us moving some work into begin phase?
* Only push newly created nodes on the parent stack
Previously I was pushing nodes on the parent stack regardless of whether they were already in current or not.
As a result, insertions during updates were duplicated, and nodes were added to existing parents before commit phase.
Luckily we have a test that caught that.
* Fix lint
* Fix Flow
I had to wrap HostContext API into a closure so that it's parameterizeable with I and C.
* Use the same destructuring style in scheduler as everywhere else
* Remove branches that don't seem to run anymore
I'm not 100% sure this is right but I can't get tests to fail.
* Be explicit about the difference between type and tag
I was confused by th HACK comment so I learned how DOM and SVG work with casing and tried to write a more descriptive comment.
It also seems like passing fiber.type into finalizeInitialChildren() is a potential problem because DOM code assumes tag is lowercase.
So I added a similar "hack" to finalizeInitialChildren() that is identical to the one we have prepareUpdate() so if we fix them later, we fix both.
* Save and restore host context when pushing and popping portals
* Revert parent context and adding children in the begin phase
We can address this later separately as it is a more hot path.
This doesn't affect correctness of SVG container behavior.
* Add a test for SVG updates
This tests the "jump" reuse code path in particular.
* Record tests
* Read ownerDocument from the root container instance
This way createInstance() depends on the innermost container only for reading the namespace.
* Track namespaces instead of creating instances early
While we might want to create instance in the begin phase, we shouldn't let DOM guide reconciler design.
Instead, we are adding a new concept of "host context". In case of ReactDOMFiber, it's just the current namespace.
We are keeping a stack of host context values, ignoring those that are referentially equal.
The renderer receives the parent context and type, and can return a new context.
* Pop child context before reading own context and clarify API
It wasn't quite clear from the API which context was being returned by the renderer. Changed the API to specifically ask for child context, and thus to pop it before getting the current context.
This fixes the case with <foreignObject> to which I intended to give SVG namespace.
* Give SVG namespace to <svg> itself
* Don't allocate unnecessarily when reconciling portals
We create stacks lazily so that if portal doesn't contain <svg>s, we don't need to allocate.
We also reuse the same object for portal host context state instead of creating a new one every time.
* Add more tests for edge cases
* Fix up math namespace
* Maintain a separate container stack
* Fix rebase mistakes
* Unwind context on errors
* Reset the container state when reusing the object
* Add getChildHostContext() to ReactART
* Record tests
Solves a few things:
- Moves code out of performWork into workLoop so that it can
be optimized.
- errorLoop (now clearErrors) is no longer called recursively.
- Removes a while (true) loop inside performWork (not that it really
matters for optimization, since performWork contains a try block and
will be deopted, anyway).
If a ref throws while detaching, it should not prevent
componentWillUnmount from being called.
Additionally, errors thrown by removeChild should not be ignored, even
as the result of unmounting a failed subtree.
Subsequent failures should propagate the error to the next boundary.
The conceptual model for this is
try {
render();
} catch (error) {
setStateToRecover();
render();
}
Closes#8485
This uncovered a separate issue where some errors were being unscheduled
and rescheduled multiple times before flushing. Turns out we need to
check both a fiber and its alternate when determining if it represents a
failed unit of work. I didn't notice this before because we were
scheduling a new update on *every* boundary at the end of the commit
phase, not just the ones that captured an error during that commit. I
updated the unit tests to catch this in the future.
We still need tryComponentWillUnmount because deletion should be non-
interruptible.
Refactoring the commit phase to better handle errors also allows us
to switch between fast and slow versions of the work loop. The slower
version runs whenever there are captured errors; it must check each
unit of work to see if it has failed. The faster version runs in the
normal case where there are no errors. Whenever an error is thrown, we
switch from the fast work loop to the slow work loop.
This makes it easier to track when we enter and exit a batch of work.
Further steps needed in this refactor:
- Get rid of tryComponentDidMount, tryComponentDidUpdate, etc. in
favor of the try-catch blocks that wrap each pass of the commit phase.
- Need to be able to switch between performing work that is possibly
failed (slower because it requires an extra check on each iteration) and
work that we know for sure has no errors.
From D4296244:
> Each [...] had a component with innerHTML = '', causing us to go into HTML parsing code in the browser. Doing this takes 0.03ms per parse call which was 10x slower than skipping it.
This fixes the issue where using the .return pointer isn't guaranteed to
return the current Fiber so we might read the wrong props when we try
to get the current event.
This is unnecessary forwarding since this is no longer injectable.
However, I'd like to use the injectable getInstanceFromNode from
TreeTraversal so this avoids a cyclic dependency.
When we perform an update to the event handler we properly update the
immediate Fiber pointer of a child to be the current. However, when we
bubble events we use the return pointer which is not guaranteed to point
to the current Fiber even if we start from the current.
This manifests itself when we bailout in a parent. So I made the tests
use a PureComponent to illustrate this scenario. There is already a failing
case but I'm adding another one too.
This strategy finds the current fiber. It traverses back up to the root if
the two trees are completely separate and determines which one is current.
If the two trees converge anywhere along the way, we assume that is the
current tree. We find the current child by searching the converged child
set.
This could fail if there's any way for both return pointers to point
backwards to the work in progress. I don't think there is but I could be
wrong.
This may also fail on coroutines where we have reparenting situations.
**What** and **Why**:
* When using npm version 2, `object-assign` and `fbjs` were not getting properly installed
* This PR adds `object-assign` and `fbjs` as explicit dependencies to both `react-test-renderer` and `react-addons`
Fixes a bug when updating from a single text child (or
dangerouslySetInnerHTML) to regular children, where the previous
text content never gets deleted.
* Exit early in scheduleUpdate if a node's priority matches
This is a performance optimization and is unobservable. However, it
helps protect against regressions on the following invariants on which
it relies:
- The priority of a fiber is greater than or equal to the priority of
all its descendent fibers.
- If a tree has pending work priority, its root is scheduled.
* New error boundary semantics
- Recovering from an error boundary no longer uses Task priority by
default. The work is scheduled using whatever priority created the
error.
- Error handling is now a side-effect that happens during the
commit phase.
- The default behavior of an error boundary is to render null. Errors
do not propagate except when an boundary fails. Conceptually, this would
be like throwing an error from a catch block.
- A host container is treated like a no-op error boundary. The first
error captured by a host container is thrown at the end of the batch.
Like with normal error boundaries, the entire tree is unmounted.
* Fix broken setState callback test
* Add test for "unwinding" context when an error interrupts rendering
* Switch over primary effect types only
This avoids the need to create an export for every combination of bits.
* Only continue the work loop if the error was successfully captured
* Add more tests for incremental error handling
These tests are currently failing:
✕ catches render error in a boundary during partial deferred mounting
✕ catches render error in a boundary during animation mounting
✕ propagates an error from a noop error boundary during full deferred mounting
✕ propagates an error from a noop error boundary during partial deferred mounting
✕ propagates an error from a noop error boundary during animation mounting
The observed behavior is that unstable_handleError() unexpected gets called twice:
"ErrorBoundary render success",
"BrokenRender",
"ErrorBoundary unstable_handleError",
+ "ErrorBoundary render success",
+ "BrokenRender",
+ "ErrorBoundary unstable_handleError",
"ErrorBoundary render error"
* Verify batched updates get scheduled despite errors
* Add try/catch/finally blocks around commit phase passes
We'll consolidate all these blocks in a future PR that refactors the
commit phase to be separate from the perform work loop.
* NoopBoundary -> RethrowBoundary
* Only throw uncaught error once there is no more work to perform
* Remove outdated comment
It was fixed in #8451.
* Record tests
* Always reset nextUnitOfWork on error
This is important so that the test at the end of performAndHandleErrors() knows it's safe to rethrow.
* Add a passing test for unmounting behavior on crashed tree
* Top-level errors
An error thrown from a host container should be "captured" by the host
container itself
* Remove outdated comment
* Separate Rethrow and Noop scenarios in boundary tests
* Move try block outside the commit loops
* Make bad element type message same as in Stack
This makes Fiber emit the same message as Stack (aside from the missing owner information).
* Add a separate test verifying error includes owner name
Fiber currently doesn't pass it. This is just to keep track of it as a todo.
This handles the case where a host text bails out. In that case we need to
reuse its previous memoizedProps. We should also only schedule an actual
update if it did actually change its text content.
I updated the unit test to ignore comment nodes if we're using Fiber.
* Add iterable cases to MultiChildReconcile test
Stack currently supports rendering iterables, but Fiber does not.
Previously we didn't have any public API tests for iterables. We have tests for traverseAllChildren() which is shared between React.Children and Stack. However Fiber doesn't currently use it, and likely won't. So this commit is a first step towards actually testing iterable support via public API. The next step will be to port traverseAllChildren() tests to test React.Children API instead.
* Implement iterable reconciliation in Fiber
This uses the same exact algorithm as array reconciliation but uses iterator to step through.
This gets reconcile tests to pass again but introduces a regression in ReactMultiChildText case which uses Maps as children. It passed before because Maps were ignored, but now it's failing because this actually runs the Map code path in Fiber. We can throw early in this case when we want to follow up on this.
* Rewrite traverseAllChildren() tests against React.Children API
This function was used in React.Children and Stack.
The corresponding reconciliation functionality is being tested by ReactMultiChild tests.
So we can move these tests to ReactChildren and test its public API.
* Use a closure to bind gaurded callback
This way the fake event isn't being implicitly passed into the event handler
* Add tests for ReactErrorUtils
Add fiber test report
Linting fixes
We used to terminate the search on host nodes, and then use the nested unmount algorithm.
However this means we didn't unmount portals inside the host nodes.
We will probably need to restructure this somehow but for now I just added a recursive call to unblock myself.
* Remove output field
The idea was originally that each fiber has a return value. In practice
most of what we're modelling here are void functions and we track side
effects instead of return values.
We do use this for coroutines to short cut access to terminal yields.
However, since this can be nested fragments we end up searching the tree
anyway. We also have to manage this in transferOutput so it ends up being
as expensive. Maybe we can save some traversal for updates when coroutine
branches bail out but meh.
* Unmount child from the first phase of a coroutine
The goal of this is to avoid passing an opaque data structure that needs
to be recursively searched by the host.
I considered having some helper for doing the recursion but I figured it
might be helpful to let the reconciler move this around. For example we
might want to create an instance in beginWork and add to it as we go.
This would let us avoid traversing the tree twice and would solve the IE11
perf issue.
So instead, we create the instance first then call appendChild. I could
just call the normal one but I figured that I would make a special one
just in case. For example if you wanted to perform commits on a separate
thread from creation. This turned out to be useful in ReactNoop where I
can avoid searching the array for an existing one since I know the child
isn't there already. (Although splitting placement into insertion/move
might be better.)
Finally, we need the ability to update an instance after all the children
have been insertion. Such as `<select value={...} />`. I called this
finalizeInitialChildren.
This removes updateContainer and instead uses the regular child mutation
methods to insert into the root container and portals.
Since we're no longer clearing out the container DOM in updateContainer
we have to do that manually during initial mount. This now works on a
document and one of the tests end up unmounting the body when you render
into the document so I had to work around that bit since we don't yet
properly support rendering into the document root.
This misbehavior is particularly egregious because of our current strategy for updating a container in Fiber, but regardless -- if we restore focus to an offscreen node (ex: because it was reordered among its siblings) then we should not scroll the page to reveal it.
We could check the `overflow` computed style values before saving the scroll positions but that's unlikely to be any faster.
I tried to add a temporary check for the correct state in https://gist.github.com/spicyj/338147e989215b6eeaf48a6ce2d68d93 and run our test suites over it, but none of our existing test cases would have triggered that invariant. The new one I added does.
* Fix browser bundle for AMD
* Final fix for standalone browser build.
Much more scientific than the rest so it should stick.
* Throw when we can't find code we need to replace.
We're walking backwards up to the root to find the parent so that we can
propagate events further up to nested React parents. If we don't find a
root, that means that the tree was unmounted and we shouldn't send any
events to it.
This was supposed to fix an issue in refs-test but instead it revealed that
this strategy is broken.
The problem is that Placement effect is not sufficient when the insertion
is completed since the effect flag is reset then and the previous tree
has no effects in it to indicate that this is the wrong tree.
If there is no child there is nothing to tell us that this was the
workInProgress branch. Therefore, we need to look at the other branch
if there are children in it to see if *that* was the workInProgress branch.
We've already been warning for mutating styles so now we'll freeze them
in DEV instead. This isn't as good because we don't have more specific
warnings than the generic error that doesn't even fire in sloppy mode.
This lets Fiber pass the same tests.
This used to be done at the end of the transaction but I made it synchronous.
For this to work it needs to be applied after we have already set the .type
property since it is read by inputValueTracker.
We need this to safely extract the current event listeners from the props.
Unfortunately, we are still not safe to use the return pointer since it
may not point to the current tree when the Fiber is reused. So this is not
fully done yet.
* Use the public ReactDOMServer in tests
We need this because it runs the injection.
* Let Fiber skip react data attributes and comments in SSR tests
This markup is testing implementation details rather than behavior.
* [Fiber] Add ReactDOMFiber.unstable_createPortal()
While #8368 added a version of `ReactDOM.unstable_renderSubtreeIntoContainer()` to Fiber, it is a bit hacky and, more importantly, incompatible with Fiber goals. Since it encourages performing portal work in lifecycles, it stretches the commit phase and prevents slicing that work, potentially negating Fiber benefits.
This PR adds a first version of a declarative API meant to replace `ReactDOM.unstable_renderSubtreeIntoContainer()`. The API is a declarative way to render subtrees into DOM node containers.
* Remove hacks related to output field
My first contribution to React!
While upgrading a React project, I found some suspect SVG that needed updating, so I dug in after checking the docs. I knew that support for some SVG properties had been added (namely `xmlns` and `xmlnsXlink`), but I noticed them missing from the reference's attribute list. This pull request updates `reference-dom-elements.md` by adding said properties.
Only declare the variable once in this scope, instead of declaring them multiple times in the same scope.
This fixes#8318, even though it might technically be a shortcoming in Rollup.
* Update all Jest packages to 17.x, cache babel-jest transforms
* Remove the caching
Looking at the other builds it doesn't seem to actually be that necessary. The bottleneck is executors, not build time.
* Remove unnecessary package, fix fiber test runner
* Regenerate yarn lockfile
I forgot that the normal properties route doesn't do this. We also have
to make sure that the order is 1) insert children (options), 2) set
multiple 3) update the options.
Wrappers operate on the raw props object instead of the processed one.
We should probably clean this up a bit since it is very confusing and
unnecessary allocations to have two separate objects for props.
To avoid exposing the implementation details of fibers we'll just pass the
DOM node around instead. We'll attach any additional wrapper state on it.
We don't have to do it that way. We can also just invert the relationship
and put the node in the wrapper state.
I'll probably just get rid of the wrapper object and just put them as
expandos on the DOM.
We read the wrapper state during initial mount for server rendering support
but Fiber doesn't use it and we don't need it. We also can't because we
haven't yet completed the parent that has the selected.
I will need to remember to always insert children before setting the
selected value on the parent <select />. That way the DOM will deal with
the `selected` property of option properly.
Instead of passing around the owner and the internal fiber everywhere we
can set current owner during each commit. That way we have it available
globally where ever we need it.
That way we don't have to pass it as a DEV only argument nor expose the
internal representation to the host config.
This doesn't actually get the current owner yet. Will do that in a follow
up.
We'll stop tracking the input value tracking. We'll also stop uncaching the
node because we can just let the garbage collector take care of that. This
makes it easier to release components in trees that never mounted.
This also removes an invariant error which is covered by unit tests.
This is necessary to separate regardless because we don't want this to
fire for a component that was started but was thrown away because it never
mounted. We can come back to that later.
Basically, we don't need to remove the event listeners because we can just
check if something is still mounted when they fire instead. We'll rely on
garbage collection to clean them up.
We don't need to wait for the commit phase to start listening to events
since we have the node.
Next we'll stop unlistening to events too and instead just check isMounted.
Fiber manages children separately so we don't need to do it here.
However, we special case the text content children and
dangerouslySetInnerHTML.
This reveals a bug that we currently don't handle the case where we switch
from dangerouslySetInnerHTML or text children to element children, because
child insertions are handled before the parent updates. We could possibly
handle this case by removing all nodes before the first host child but
that is a bit unfortunate.
We have warned about not mutating styles already. At this point we can just
freeze the style object in DEV.
That way we can read it from the previous props object without storing
another copy of it.
Also delete the associated warning.
* Update ESLint to 3.10.2
Also pull in fbjs for extending properly, per @zpao. This also disables consistent-return, which has about 80 failing cases in React currently. If we'd like to turn this back on, we should do it separately and fix all the call sites properly (rather than just adding 'return undefined;' everywhere, which adds no value.
Fixes to all existing lint errors plus an update for yarn.lock to follow.
* Update yarn.lock after the eslint update.
* Fix all new eslint failures
Unfortunately I had to add three eslint-disable-next-line instances. All have explanations inline.
* Switch Travis to use yarn instead of npm
Showing how to create a form without labeling inputs is an accessibility anti-pattern. This change adds labels to the examples to address that. Codepen may still need to be updated depending on how that example is created.
* Update tutorial.md
Is it possible to be more clear here?
This implies that we are removing the constructor from GAME, and not board (which is what I believe the author is trying to say).
It took me several reads to understand.
With this edit, it is now clear that the adjustment is being made to -Board- and not to -Game-
* also remove "for Board earlier"
* Remove spread operator
I believe what was meant here was to express that you would create the new player object with all the previous properties of the existing player object in addition to now updating the score value. That being said, this is a simple example, and the player object clearly has no other values. Objects are not (by default) iterable using this operator, so this little piece does more harm than good. I believe the new example to be much clearer.
* Using Object.assign()
* Tweak wording
This traverses parent based on the type of internal instance it is passed.
If it is a Fiber it may have to traverse multiple steps until it finds a
HostComponent.
This will allow us to use the event system with Fiber.
This adds precaching to ReactDOMFiber. I.e. adding a handle from the DOM
node to the internal Fiber. This means that we need to expose an internal
handle to the reconciler.
We use duck typing to figure out if it is a Fiber or Stack instance.
The new failing tests are failing because this is now able to actually
fire events onto Fibers and then the result of those events are
incorrect where as they were ignored before.
* Reapply Check for event listener in props instead of bank (#8192)
This reverts the previous revert.
* Don't throw on falsy event listeners
Some code relies on passing null. This restores the earlier behavior.
This matches Stack behavior.
Had to rewrite a test that used Simulate because Fiber doesn't support events yet.
Also changed tests for componentDidUpdate() since Fiber intentionally doesn't pass prevContext argument.
We can avoid recreating the merged context object if the context provider work was reused. This is essential to avoid allocations for deep setState() calls.
As per discussion, this is better because then this code only runs for the class type of work. We will still need to fix bailouts for deep setState calls.
It is error-prone to push and pop context in begin or complete phases because of all the bailouts. Scheduler has enough knowledge to see if pushing is necessary because it knows when we go inside or outside the tree.
I'll plan to change all of our console.error and component-tree expects to expectDev. It's a little annoying that we need to make sure tests don't throw (see my change to normalizeCodeLocInfo) but any alternative would seem to require two separate test runs or a much more cumbersome syntax.
* Handles risky callbacks on setState. Fixes#8238
* Updates try-catch to cover `callback` when context is not present.
* Updates code to trapErrors instead of swallowing them.
* Fixes flow errors
* Incorporates review comments
* Traps only the first error.
Removes `callbackWasCalled` and updates fiber tests.
I came up with a contrived case of where nested controlled events could
fire within the same batch - but on different targets.
I think we came to the conclusion that controlled values typically cannot
use preventDefault so it is ok that they don't flush until after the event
has finished. So therefore we accumulate a queue of all the nested targets
within a batch and then restore state on all of them.
I'm still skeptical that this is the correct way to do controlled values.
The reason we have to do them in a single event loop is because when you
type, the sequence of values that get accepted or not can matter. I wonder
if there is a scenario we can come up with where you can fire multiple
inner events in an event loop and end up with batching causing problems.
This effectively just reimplements asap again but with no allocations for
a single target and no closure allocations.
* Make the Shallow Rendering example clearer
I was reading through the documentation, and I found that the `render` call on the `renderer` was missing.
* Use a regular function to define MyComponent
* Use _hostContainerInfo to track test renderer options
The transaction is not available when unmounting or updating the
instance, so we track it using _hostContainerInfo
* Throw if hostContainerInfo is not populated in getPublicInstance
* Linting fixes
* Remove transaction from ref lifecycle code path
We don't need to pass the transaction around anymore since we store the
test options on _hostContainerInfo instead
* Remove unused argument
If a controlled target fires within another controlled event, we should not
restore it until we've fully completed the event. Otherwise, if someone
reads from it afterwards, they'll get the restored value.
Not super happy with this particular solution.
* took codes.json from the 15-dev branch
* fixed react:extract-errors task in gulpfile
* generated error codes
* Revert "generated error codes"
This reverts commit b8f3aeed9d8f0d469edd5f6623fa6090930594d8.
* Added a README for the error code system
This reverts commit a878c3056d.
The previous stuff that this builds on didn't successfully land fully. Since I
want to measure this in isolation, I'll revert this for now.
This just reads events from the props instead of storing them in a
listener back.
I had to rewrite a bunch of tests to cover this model.
I removed the tests that just test the adding and removing over listeners
since there is no equivalent behavior anymore.
This reverts the implementation in 33325ad009.
I didn't mean to merge the implementation since it is incorrect and incomplete.
I meant to just merge the unit test.
* Ensure that we're listening to all onChange dependencies for controlled inputs
When there is no onChange event handler, we should still listen to it to
ensure controlled values get reset.
There is warning associated with this but the prod behavior should still be
respected.
* Rerun tests
When there is no onChange event handler, we should still listen to it to
ensure controlled values get reset.
There is warning associated with this but the prod behavior should still be
respected.
* Use explicit pass for restoring controlled state instead of asap
This gets rid of the first class ReactUpdates.asap scheduling. Instead of
scheduling a first class function to invoke later, I introduce an explicit
phase for restoring controlled state after dispatching events.
We assume that the deepest event target is the thing that needs its state
restored.
* Drop special cases for onChange in wrappers
We're now not using anything special about onChange handling in the
wrappers. Yay!
* Attempt to fix ReactDOMTextComponent test in Fiber
Obviously, some tests pass but the reconciliation is still incomplete on this in Fiber.
Those changes just ignore reconciliation Comments while asserting (this fixes 2 tests already) but now shows that Fiber lacks some reconciliation features.
* Transmit a parentInstance to commitTextUpdate
This is done in case a Node#normalize() was performed on the parent instance and that the TextInstance got desolidarized from the parent. We provide the parent known by the parent Fiber to reattach the DOM node in this case.
* Added a more complex case around split nodes
This test does not assume one split node substitution alone but also some non-split nodes.
* Fiber supports split text nodes
This is done by suppressing nodes appearing during the split. this is based by comparing against the old value known by the Fiber.
* Simplify siblings cleaning in commitTextUpdate
No need to assert instanceof Text since the length comparator will work correctly.
* Ensure non-text nodes won't be removed
* Fix flow for Fiber Text reconciliation additions
Mostly define types as optionals. Respects the strict DOM API around Node & Element.
* Append at any stack stage only if necessary
The direct parent of the TextNode fiber may not contain the host node. We have to go through the hierarchy. However, since this work may be expensive, we only do it if absolutely necessary!
* Use tag & ReactTypeOfWork to find an HostComponent
* Addfailing scenario when running Node.normalize()
It happens when non-text-elements are added in the mix. @sebmarkbage seems to have an idea on how to fix it. This is just a repro of the bug!
* Register failing/passing fiber tests
This gets rid of the global flag on if something has listened to onSelect
and instead reads the isListening map if all the events are covered.
This is required if we want to attach events locally at roots.
Could be slower perf wise to handle events. An alternative solution would
be to attach a special flag on the listener map for the document so we
don't have to check the full dependency list.
However, my favorite solution would be to just eagerly attach all event
listeners (except maybe wheel). Then we don't have to do any of this stuff
on a per element basis.
* Print a warning in fiber for lacking render method
* Reject initial non-object state in Fiber
Rejects Arrays, Strings & Numbers. Allows nulls.
* Centralize fiber checks on ES6 Classes
* Add classic & instance property checks on fiber
- check the absence of getInitialState & getDefaultProps as methods
- check the absence of propTypes & contextTypes at instance-level
* Convert to normalized React `warning` calls
* Support lifecycle typo detection in fiber
* Get the complete warnings from the existing code
* Only check classInstance once
Avoid rechecking while resuming
* Can warn component while resuming but only once
This is achieved by tracking the warning state in the Fiber structure.
* Remove warning deduplication
* Factor name retrieval in a getName helper
* Use invariant instead of throw
* Read inst.state only once for the invariant
* Fix condition on the instance state
* Register failing/passing fiber tests
* Check if textContent should be set for textarea
shouldSetNodeTextContent returns whether a node.textContent should be
updated. Currently it only covers one case, which is to avoid setting
the textContent if the text is empty and a placeholder exists.
* Only set node.value if it's equal to initialValue
In IE11 textContent is populated when the placeholder attribute is set.
Without this check, we end up setting node.value equal to the
placeholder text, causing the textarea to actually render with the text
inside.
This check makes sure that textContent is equal to our expected
initialValue, which should be the case when using defaultValue.
* Remove placeholder/textarea check, use contentToUse instead
* Refactor scheduling functions and introduce Task priority
There was lots of duplication across all the scheduling functions. I
think we're far enough along that we can start trying to clean some
stuff up.
Also introduces a new priority level provisionally called Task priority.
This is for work that completes at the end of the current tick, after
the current batch of work has been committed. It's different from
Synchronous priority, which needs to complete immediately.
A full implementation of Task priority will follow. It will replace
the current batching solution.
* Implement Task priority
Task priority is similar to Synchronous priority. Both are flushed in
the current tick. Synchronous priority is flushed immediately (e.g. sync
work triggered by setState will flush before setState exits), where as
Task is flushed after the current batch of work is committed.
Currently used for batchedUpdates and nested sync updates. Task should
also be used for componentDidUpdate/Mount and error boundary work. I'll
add this in a later commit.
* Make error boundaries use Task Priority
I have all but one error fixed. Not sure how tricky the last one is,
but I'm cautiously optimistic. Pushing to show my current progress.
* Remove recursion from handleErrors
Changed the algorithm of handleErrors a bit to ensure that boundaries
are not revisited once they are acknowledged.
* Add incremental error boundary test
Discovered an edge case: a noop error boundary will break in incremental
mode unless you explicitly schedule an update.
* Refactor error boundaries in Fiber
* Simplify trapError() calls
The existing logic was written before we had a proper error handling system.
* Remove unnecessary flags
* Prevent performTaskWork recursion
* Be stricter about preventing recursion
Before, this code was bailing out after encoutering a null child because it thought it was out of old children. Seen when reconciling [null, <span />, <Image />] with [null, <span />, <Image />] in XUISelector.
This is already where we trap non-bubbling events. We also already branch
on the tag type so we know if it is interactive or not.
This will let us get rid of the didPutListener and willDeleteListener
abstractions.
I use a simple onclick = emptyFunction to avoid the need for a bookkeeping
map.
Covers some bugs I encountered while working on this feature.
Introduces a syncUpdates API to ReactNoop. Is this something we'd want
to expose to the reconciler?
Without this fix, in non-batched mode, the update is scheduled first and
synchronously flushed before the callback is added to the queue. The
callback isn't called until the next flush.
A bit of restructuring so that setState uses whatever the current
priority context is, like top-level render already does.
Renamed defaultPriority to priorityContext, and added a new variable
called defaultPriorityContext. Having two separate variables allows the
default to be changed without interfering with the current context.
This removes an optimization that avoids call update on ReactDOMSelect
twice in an onChange event.
2601b6a0b0 (commitcomment-19643403)
None of the other controlled components do this. The only reason to do it
here is because of the loop.
I'd like to remove this because I'd like to remove all the side-effects
that happen in onChange, other than user defined behavior. I'd also like to
get rid of state that track sequences. It is easier if everything is just
diffing.
Alternatively I can store the previous value that we processed and only
reprocess if the value has changed. However, that would requires the array
for multiple values to be immutable and I don't think we enforce that
right now.
In Fiber, I believe that we'll be able to batch both these updates into a
single commit.
Instead of scheduling individual callbacks to asap, we schedule one and
then do all the work in that one.
I'm doing this for architectural refactoring reasons.
Nevertheless, I'm adding a contrived unit test that this fixes. :)
The type of `ReactFiber.Fiber.effectTag` is `TypeOfSideEffect`.
Thus we should assign `ReactTypeOfSideEffect.NoEffect` value instead of
`ReactPriorityLevel.NoWork` even if they are same values.
* Make test more complete
* Add a failing test for scheduling in reverse order
It hangs forever because we don't clear next pointer when unscheduling a root. Therefore, when it's scheduled again, it brings all its previous chain with it, potentially creating a cycle.
* Clear the next pointer when unscheduling a root
Fixes a potential infinite cycle when we reschedule a root.
* Add new tests to Fiber test tracker
This should be safe because we've been warning for this. The LinkedStateMixin is technically exposed on React.addons without a warning but presumably you wouldn't be using it without a valueLink or checkedLink.
I do this primarily to clear up what the custom onChange listeners are doing.
Renamed the final prop type helper to ReactControlledValuePropTypes.
Gets rid of an obsolete word in the documentation for "State and Lifecycle":
"Consider the ticking clock example from the one of the previous sections."
->
"Consider the ticking clock example from one of the previous sections."
* Test Fiber internals differently in ReactElement
Instead of being able to access the owner's instance via getPublicInstance(), we use the Fiber's stateNode. (Fiber does not have methods, it's just a structure!)
* Fix isCompositeComponentWithType for fiber
In ReactTestUtils.isCompositeComponentWithType, we provide a way to walk through Fiber's internals in place of using _currentElement.type. We keep support for non-fiber though.
* Test fiber reconciler consistently
Use typeof instance.tag to test if we're using the fiber reconciler
* Remove unnecessary comment
Now that commits are treated as atomic, it is possible that componentDidMount, componentDidUpdate, or componentWillUnmount threw in multiple places during the commit. We need to make sure we notify all affected boundaries of the first errors in them.
This moves calls that don't know if they're in a Fiber or Stack
context to use ReactGenericBatching.batchedUpdates.
The corresponding one will be injected from either the stack
reconciler and/or the fiber reconciler if they're loaded at the
same time.
This lets them share the event system when they're both used
at once.
This can also be useful for libraries that call
unstable_batchedUpdates today but don't know which renderer to
use.
Instead of relying on IDs, we now use instances for everything so
this should be reflected by the test.
This still has a _rootNodeID to store the listeners which I will
remove next.
The code section above these changes defines a `formatName` function
that expects a parameter `user`. The code section containing these
changes incorrectly called `formatName(user.name)`. For those following
along with CodePen, this section should correctly call
`formatName(user)`.
Prior to this, React was using a nextDebugID variable that was locally
scoped to both `instantiateReactComponent` and `ReactShallowRenderer`.
This caused problems when the debugIDs would collide, the `itemMap` in
`ReactComponentTreeHook` would be overwritten and tests would fail
with the message "Expected onBeforeMountComponent() parent and
onSetChildren() to be consistent".
This change shares the debugID with both modules thus preventing any
collisions in the future.
* Reapplied fixes to updated docs from master
* Reapplied fixes to Forms, removed ES2016 function includes()
* Missing carriage return
* Adding back some line breaks
* Making requested changes.
* Making space changes
* Fixed typo and removed unnecessary hyphen.
* Reworded select, and highlighted line
* Fixed string styles
* Refactored <label> to use htmlFor
* Another refactor of <label>
* Removed name prop from radiobutton
* Reapplied fixes to updated docs from master
* Reapplied fixes to Forms, removed ES2016 function includes()
* Missing carriage return
* Adding back some line breaks
* Making requested changes.
* Making space changes
* [Fiber] Add top level render callbacks into ReactDOMFiber and ReactNoop
* [Fiber] Support multiple render callbacks
* [Fiber] `this` in render callbacks are public instances
* [Fiber] commitLifeCycles move to behind the effectTag check
* Implement string refs using callback closures
* Merge Fiber type to avoid Flow intersection bugs
Still one remaining type error that I'm not sure how to fix
* Fix Flow issue with an unsafe cast
* Fix missing semicolon
* Add a type import I missed earlier
This fix relies on the props and state objects being different
to know if we can avoid a componentDidUpdate. This is not a great
solution because we actually want to use the new props/state
object even if sCU returns false. That's the current semantics
and it can actually be important because new rerenders that are
able to reuse props objects are more likely to have the new props
object so we won't be able to quickly bail out next time.
I don't have a better idea atm though.
These two implementations are identical. Except for some
invariants for some reason.
Since this relies on an implementation detail of the internal
component tree rather than an implementation detail of the
renderer, we might as well merge them and remove the injection.
These are new features that aren't covered by existing tests.
It is now possible to use findDOMNode to find a text node.
When a component returns a fragment, it will search to find the
first host component just like element.querySelector does.
First we need to check if a component subtree is mounted at all.
If it is, we need to search down the fiber for the first host
node. However, we might be searching the "work in progress"
instead of current.
One realization is that it doesn't matter if we search work in
progress or current if they're the same. They will generally be
the same unless there is an insertion pending or something in
the alternate tree was already deleted. So if we find one of
those cases, we switch to look in the alternate tree instead.
There are two cases where we have a Fiber that is not actually
mounted. Either it is part of a tree that has not yet been
inserted or it is part of a tree that was unmounted.
For the insertion case, we can check the parents to see if there
is any insertion effect pending along the parent path.
For deletions, we can now check if any of the return pointers
is null without actually being the root.
This is the naive implementation that doesn't cover the case
where it has completed but not yet committed. It also doesn't
deal with unmounts since they currently don't clean up the item
in the ReactInstanceMap.
This is just moving a bunch of DOM files.
It moves things into dom/stack and dom/fiber respectively. The
dom/stack folder remains split into client/server.
Mainly the shared folder is now my best guess for files that
we can reuse in fiber. Everything else will get forked or
reimplemented.
Also moved the event system out of renderers/shared/stack and
into renderers/shared/shared.
When keys line up in the beginning but the type doesn't
we don't currently delete the child. We need to track that this
fiber is a not a reuse and if so mark the old one for deletion.
This splits DefaultInjection into one with all the properties
and event configuration and a separate one for the things that
are relevant to he stack reconciler.
That way we can reuse the property and event system for Fiber
without pulling in all the other stuff.
This isn't a complete solution to all attributes. It's just that
we run a lot of unrelated unit tests by testing className so
we need it for the tests.
The tutorial wants to throw a 'warning' and explains about 'key' of React's list, but it throws nothing since there is sensible key.
"key={move}" should be removed, and added after explaining about key.
* Consider Host Component classes when creating a new internal instance
* Remove unused tagToComponentClass & injectComponentClasses from ReactHostComponent
This doesn't deal with the fact that work is usually deferred
so this will return null for first render (except in sync tests).
It also doesn't deal with top levels being fragments etc.
It doesn't deal with the host instance type being a wrapper
around the public instance. This needs to be unified with refs
and findDOMNode better.
However, this does expose that we reactComponentExpect and
ReactTestUtils doesn't work very well with Fiber.
If work has progressed on a state update that gets resumed
because of another state up, then we won't have an new
pendingProps, and we also won't have any memoizedProps because
it got aborted before completing. In that case, we can just
fallback to the current props.
I think that they can't have diverged because the only way they
diverge is if there is new props.
This lets us bail out on state only updates in more cases which
the unit tests reflect.
We currently only filter out "NoWork" in the beginning of this
function. If the NoWork root is after the one with work it will
show up in the second loop. There's probably a more efficient
way of doing this but this works for now.
This showed up in this PR because a new unit test gets unblocked
which ends up with this case.
This refactors the initialization process so that we can share
it with the "module pattern" initialization.
There are a few new interesting scenarios unlocked by this.
E.g. constructor -> componentWillMount -> shouldComponentUpdate
-> componentDidMount when a render is aborted and resumed.
If shouldComponentUpdate returns true then we create a new
instance instead of trying componentWillMount again or
componentWillReceiveProps without being mounted.
Another strange thing is that the "previous props and state"
during componentWillReceiveProps, shouldComponentUpdate and
componentWillUpdate are all the previous render attempt. However,
componentDidMount's previous is the props/state at the previous
commit. That is because the first three can execute multiple
times before a didMount.
I couldn't figure out how to do this yarn alone so I ended up
just manually hacking the yarn to force a downgrade of babylon
to 6.8.0 since otherwise it gets resolved to 6.12.0 which is
broken.
* Use the memoized props/state from the workInProgress
We don't want to use the "current" props/state because if we have
started work, then pause and continue then we'll have the newer
props/state on it already. If it is not a resume, it should be the
same as current.
* Deprioritize setState within a deprioritized tree
Currently we flag the path to a setState as a higher priority
than "offscreen". When we reconcile down this tree we bail out
if it is a hidden node. However, in the case that node is already
completed we don't hit that bail out path. We end up doing the
work immediately which ends up committing that part of the tree
at a higher priority.
This ensures that we don't let a deprioritized subtree get
reconciled at a higher priority.
* Bump idx in unit test
This proves that this number is actually deprioritized.
Refactors the class logic a bit.
I moved scheduleUpdate out into the scheduler since that's where
the scheduling normally happens. I also moved it so that we can
rely on hoisting to resolve the cycle statically.
I moved the updater to a new class component file. I suspect we
will need a bit of space in here since the class initialization
code is quite complex.
The class component dependency is currently fixed in BeginWork
so we can't move complete or commit phase stuff to it. If we need
to, we have to initialize it in the scheduler and pass it to the
other phases.
If we abort work but have some completed, we can bail out if
the shouldComponentUpdate returns true. However, then we have
a tree that is low priority. When we bailout we currently use
the "current" tree in this case. I don't think this is right.
I'm not sure why I did that.
Similarly, when we complete we use the "current" props if we
didn't have pending props to do. However, we should be using
the memoized props of that tree if it is a pending work tree.
Added a unit test that covers these two cases.
This reorganizes the two commit passes so that all host
environment mutations happens before any life-cycles. That means
that the tree is guaranteed to be in a consistent state at that
point so that you can read layout etc.
This also lets us to detach all refs in the same pass so that
when they get invoked with new instances, that happens after it
has been reset.
During the deletion phase we call detachRefs on any deleted refs.
During the insertion/update phase we call attachRef on class
and host components.
Unfortunately, when a ref switches, we are supposed to call all
the unmounts before doing any mounts. This means that we have to
expact the deletion phase to also include updates in case they
need to detach their ref.
These happen in the commit phase *before* the setState callback.
Unfortunately, we've lost the previous state at this point since
we've already mutated the instance. This needs to be fixed
somehow.
While we're deleting nodes, we need to call the unmount
life-cycle. However, there is a special case that we don't want
to keep deleting every host node along the way since deleting the
top node is enough.
We only use the effect list when we reuse our progressed children.
Otherwise it needs to reset to null.
In all other branches, other than bailoutOnLowPriority, we
revisit the children which recreates this list.
We should also not add fibers to their own effect list since it
becomes difficult to perform work on self without touching the
children too. Nothing else does that neither.
Since that means that the root isn't added to an effect list we
need to special case the root.
This shortcut had a bug associated with it. If beginWork on this
child returns null, then we don't call completeWork on that fiber.
Since removing this short cut adds another time check, we have to
add a single unit of time in tests to account for the top level
call now taking one more unit.
This was also the only recursive call in all of fiber so it's nice
to get rid of it to guarantee that a flat stack is possible.
Instead of passing the full list of children every time to
update the host environment, we'll only do inserts/deletes.
We loop over all the placement effects first and then later
we do the rest.
First clear any progressed deletions for any case where we start
over with the "current" set of children.
Once we've performed a new reconciliation we need to add the
deletions to the side-effect list (which we know is empty because
we just emptied it).
For other effects, instead of just adding a fiber to an effect
list we need to mark it with an update. Then after completion
we add it to the the effect list if it had any effects at all.
This means that we lose the opportunity to control if a fiber
gets added before or after its children but that was already
flawed since we want certain side-effects to happen before others
on a global level.
Instead, we'll do multiple passes through the effect list.
When we reconcile children we need to track the deletions that
happen so that we can perf side-effects later as a result. The
data structure is a linked list where the next pointer uses the
nextEffect pointer.
However, we need to store this side-effect list for reuse if we
end up reusing the progressedChild set. That's why I add a
separate first/last pointer into this list so that we can keep it
for later.
When we don't have any previous fibers we can short cut this path
knowing that we will never have any previous child to compare to.
This also ensures that we don't create an empty Map in this case.
We use this to track the index slot that this Fiber had at
reconciliation time. We will use this for two purposes:
1) We use it to quickly determine if a move is needed.
2) We also use it to model a sparce linked list, since we can have
null/false/undefined in our child set and these take up a slot for
the implicit key.
This implements the first step to proper child reconciliation.
It doesn't yet track side-effects like insert/move/delete but has
the main reconciliation algorithm in place.
The goal of this algorithm is to branch early and avoid rechecking those conditions. That leads to some duplications of code.
There are three major branches:
- Reconciling a single child per type.
- Reconciling all children that are in the same slot as before from the beginning.
- Adding remaining children to a temporary Map and reconciling them by scanning the map.
Even when we use the Map strategy we have to scan the linked list to line up "same slot" positions because React, unlike Inferno, can have implicit keys interleaved with explicit keys.
We'll enable updating of text nodes. To be able to test that we
need the text nodes to be mutable. They're currently just strings
in the Noop renderer so this makes them an object instead.
That exposed a bug in ReactFiberCommitWork for text nodes.
This needs to be fixed somehow. The reconciler could know if you
are mounting this continuation into the same spot as before and
then clone it. However, if the continuation moves, this info is
lost. We'd try to unmount it in one place and mount the same fiber
in another place.
Dropped the unnecessary use of findDOMNode.
Dropped unnecessary arrow functions.
Math.random() -> id counter, since this used to be
non-deterministic which is not ideal for unit tests.
getOriginalKeys() used to rely on implementation details
to scan that the internal data structure maintained its
structure, however, since that is unobservable we don't
need to test the internal data structure itself. We're
already testing refs and dom structure which is the only
observable effect of the reorder.
These nodes rendering into Text nodes in the DOM.
There is a special case when a string is a direct child of a host
node. In that case, we won't reconcile it as a child fiber. In
terms of fibers, it is terminal. However, the host config special
cases it.
It is kind of unfortunate that we have to special case this kind
of child in the HostConfig. It would be nice to unify this with
other types of child instances. Text nodes have some weird special
cases, but those special cases tend to *vary* by environment.
They're not the same special cases so not sure how valuable it is
to have a special protocol and special types for it.
We currently treat nested arrays as a unique namespace from top
level children. So that these won't share key namespaces. This
adds a new fiber type that will represent the position of a
fragment.
This is only used for nested arrays. Even if you return an array
from a composite component, we don't need this since they share
namespace with a single top level component.
This still doesn't implement the complete reconciliation
algorthim in child fiber. That's coming later.
Otherwise Flow finds obscure files in docs/vendor.
Seems like you'd only get them if you have a local checkout of docs Ruby dependencies.
This explains why Travis didn't fail.
* Initial pass at the easy case of updates (updates that start at the root).
* Don't expect an extra componentWillUnmount call
It was fixed in #6613.
* Remove duplicate expectations from the test
* Fix style issues
* Make naming consistent throughout the tests
* receiveComponent() does not accept safely argument
* Assert that lifecycle and refs fire for error message
* Add more tests for mounting
* Do not call componentWillMount twice on error boundary
* Document more of existing behavior in tests
* Do not call componentWillUnmount() when aborting mounting
Previously, we would call componentWillUnmount() safely on the tree whenever we abort mounting it. However this is likely risky because the tree was never mounted in the first place.
People shouldn't hold resources in componentWillMount() so it's safe to say that we can skip componentWillUnmount() if componentDidMount() was never called.
Here, we introduce a new flag. If we abort during mounting, we will not call componentWillUnmount(). However if we abort during an update, it is safe to call componentWillUnmount() because the previous tree has been mounted by now.
* Consistently display error messages in tests
* Add more logging to tests and remove redundant one
* Refactor tests
* Split complicated tests into smaller ones
* Assert clean unmounting
* Add assertions about update hooks
* Add more tests to document existing behavior and remove irrelevant details
* Verify we can recover from error state
* Fix lint
* Error in boundary’s componentWillMount should propagate up
This test is currently failing.
* Move calling componentWillMount() into mountComponent()
This removes the unnecessary non-recursive skipLifecycle check.
It fixes the previously failing test that verifies that if a boundary throws in its own componentWillMount(), the error will propagate.
* Remove extra whitespace
The script that strips providesModule is very sensitive.
Test plan:
Searched for providesModule in build. No more.
reactComponentExpect used to have problems too but doesn't seem
to anymore. Don't know why.
* Add warning for shady-dom use with rendered react components in DEV
* Make shady dom warning emit only once regardless of number of components
* Use didWarnShadyDom as warning argument & add missing shadyRoot check to ReactDOMComponent
* Add check for shady dom test to run only when createElement flag is true
* Pass false to warning in shadyDom warning check
* Add consistent DOM phrasing for shady DOM warnings
* Reference component name in shady DOM warning if it exists
* Add check for if owner exists in shady dom warning
* Add test for named component using createClass for shady DOM warning
* Clean up named component test for shady DOM warning
* Fix trailing comma linting issue on named shady DOM warning test
Before this change calling renderToStringImpl would inject
ReactDefaultBatchingStrategy after completion, even if a custom batching
strategy was injected before. This makes renderToStringImpl keep a reference to
the batching strategy before it runs and reinject it afterwards.
* Add more to Codebase Overview
* WIP
* Start a reconciler overview
* Add a few more sections
* todo
* WIP
* Finish it
* Whitespace
* Minor tweaks
* Minor tweaks
* Ensure lib/ is packaged for react-test-renderer
* Run npm pack from right working directory
We were running this on the original packages not the compiled ones, resulting in missing files
* Reduce confusion in testing documentation.
Just wanted to add some clarity to this page and link to the react tutorial on Jest's website to give people more information. Also changed enzyme's definition from library to utility to help reduce the confusion. Hope this makes sense to everybody :)
See https://twitter.com/damusnet/status/780752042675597312
cc @lelandrichardson
* Update 10.4-test-utils.md
* Add a hook that throws a runtime warning for invalid WAI ARIA attributes and values.
* Resolved linting errors.
* Added a test case for many props.
* Added a test case for ARIA attribute proper casing.
* Added a warning for uppercased attributes to ReactDOMInvalidARIAHook
When you put the output of a bash command in a variable, it replaces the `\n` with a space. Using `ls` instead of `echo` fixes it
Test Plan:
Run
```
ALL_FILES=`find src -name '*.js' | grep -v umd/ | grep -v __tests__ | grep -v __mocks__`
COUNT_ALL_FILES=`ls $ALL_FILES | wc -l`
echo $COUNT_ALL_FILES
```
Make sure that it outputs 221
Use the newly added tracking system to track the number of fiber tests that are passing/failing.
I first tried to modify the grunt lint rule for it and send the output in stdout but unfortunately grunt displays the rule + done messages there. I had like 30 lines of js already and I figured I could just write 3 lines of bash and it would work the same. Let me know if you want me to use another approach for it.
Test Plan:
Run the commands that have been introduced in this commit but the facts-tracker one
Run `echo $FIBER_TESTS` and make sure it prints `666/1434`
* Introduce facts-tracker
We want to be able to track various things like number of files that are flowified, number of tests passing with Fiber...
This introduces a tool that lets you do that. The API is very simple, you execute the script with a list of tuples [key value] and it's going to create a `facts` branch and put a txt file for each fact and values over time.
```
node scripts/facts-tracker/index.js \
"flow-files" "$COUNT_WITH_FLOW/$COUNT_ALL_FILES"
```
Test Plan:
This is tricky to test because Travis only exposes the private variables (github token) when it processes a committed file and not on branches. The reason is that otherwise anyone could send a pull requests that does `echo $GITHUB_TOKEN` and steal your token.
Given this constraint, I did all the work using two of my repos:
- https://github.com/vjeux/facts-tracker
- https://github.com/vjeux/facts-tracker-test
and am sending this pull request that should work as is /fingers crossed/, but we won't be able to test it out until it is committed.
Note that once this lands, I'm going to kill those two repos.
* Update with all the suggested changes
* Branch on a flow type in travis.yml
* Use $GITHUB_TOKEN
* properly escape it
* Resolve flow errors with ReactTestRenderer
* Add whitespace between types and methods
* extend ReactMultiChild instead of using Object.assign
* Use ReactElement type from ReactElementType
* Make ReactMultiChild a class
This ensures we ignore relative to our project root and won't be tripped up by issues where checkouts in other places result in Flow passing when it shouldn't (eg on Travis CI where the checkout path is `/home/travis/build/facebook/react`)
* High priority work
Adds the ability to schedule and perform high priority work. In the
noop renderer, this is exposed using a method `performHighPriWork(fn)`
where the function is executed and all updates in that scope are given
high priority.
To do this, the scheduler keeps track of a default priority level.
A new function `performWithPriority(priority, fn)` changes the default
priority before calling the function, then resets it afterwards.
* Rename overloaded priority terms
"High" and "low" priority are overloaded terms. There are priority
levels called HighPriority and LowPriority. Meanwhile, there are
functions called {perform,schedule}HighPriWork, which corresponds
to requestAnimationFrame, and {perform,schedule}LowPriWork, which
corresponds to requestIdleCallback. But in fact, work that has
HighPriority is meant to be scheduled with requestIdleCallback.
This is super confusing.
To address this, {perform,schedule}HighPriWork has been renamed
to {perform,schedule}AnimationWork, and
{perform,schedule}LowPriWork has been renamed to
{perform,schedule}DeferredWork. HighPriority and LowPriority
remain the same.
* Priority levels merge fix
This also buffers all rows into a single console.log call.
This is because jest nows adds the line number of each console.log
call which becomes quite noisy for these trees.
This is unfortunate since we agreed on using the `null | Fiber`
convention instead of `?Fiber` but haven't upgraded yet and this
is the pattern I've been using everywhere else so far.
We should be able to abort an update without any side-effects to the
current tree. This fixes a few cases where that was broken.
The callback list should only ever be set on the workInProgress.
There's no reason to add it to the current tree because they're not
needed after they are called during the commit phase.
Also found a bug where the memoizedProps were set to null in the
case of an update, because the pendingProps were null. Fixed by
transfering the props from the instance, like we were already doing
with state.
Added a test to ensure that setState can be called inside a
callback.
Callbacks are stored on the same queue as updates. They care called
during the commit phase, after the updates have been flushed.
Because the update queue is cleared during the completion phase (before
commit), a new field has been added to fiber called callbackList. The
queue is transferred from updateQueue to callbackList during completion.
During commit, the list is reset.
Need a test to confirm that callbacks are not lost if an update is
preempted.
Rather than bubble up both trees, bubble up once and assign to the
alternate at each level.
Extract logic for adding to the queue to the StateQueue module.
Updates are scheduled by setting a work priority on the fiber and bubbling it to
the root. Because the instance does not know which tree is current at any given
time, the update is scheduled on both fiber alternates.
Need to add more unit tests to cover edge cases.
This colocates the reliance on alternate with the scheduler, so
that we have the option to not use this, or more easily break
apart the initial mount phase into an optimized path.
I'll probably end up reverting this before the bigger release
since it is not part of the official public API. However,
it is useful to be able to compare the performance between
functional components and classes.
The findPendingWork phase is the same as just walking the tree the
normal way effectively. It only makes things more complex to
think about. We might possibly be able to write a few special
branches to optimize it but for now it doesn't seem necessary.
The priority level gets reset at the wrong time because I rely
on mutating it at the wrong point. This moves it to the end of
completed work as a second pass over the children to see what
the highest priority is. This is inefficient for large sets but
we can try to find a smarter way to do this later. E.g. passing
it down the stack.
This bug fix revealed another bug that I had flagged before that
we're finding work to do in the "current" tree instead of the
working tree. For trees that were paused, e.g. childInProgress
trees, this won't work since don't have a current tree to search.
Therefore I fixed findNextUnitOfWorkAtPriority to use
workInProgress instead of current.
* Implement optional mockConfig and getMockRef
* default mockConfig, walk render tree
* Pass mockConfig to transaction
* Attach mockConfig to transaction
* type mockConfig in ReactRef
* Expect object in native component ref test
* Fix argument name for attachRefs
* Add mockConfig support to legacy refs
* Pass transaction to getPublicInstance
* Implement getMockConfig on ReactTestReconcileTransaction
* Merge defaultMockConfig and mockConfig options
* Rename mockConfig to testOptions
* Break getPublicInstnce into three lines
* createMockRef -> createNodeMock
Due to a typo in PR#7667 where I put 'DispatchConfig' when the type was
'EventTypes', there were some flow errors being thrown.
Then PR#7642 fixed a bug in SimpleEventPlugin and added some untyped
methods, which threw more flow errors.
Last, while fixing this, I fixed two eslint errors in the
SimpleEventPlugin test.
* Cull disabled mouse events at plugin level. Remove component level filters
* DisabledInputUtils tests are now for SimpleEventPlugin
* Add click bubbling test
* Add isInteractive function. Use in iOS click exception rules
* Invert interactive check in local click listener. Add test coverage
* Reduce number of mouse events disabable. Formatting in isIteractive()
* Switch isInteractive tag order for alignment
* Update formatting of isInteractive method
To demonstrate multiple arguments `bind(this, arg1, arg2, ...)`, also not to pass in for than what `handleClick` needed, namely props, or maybe even pass item itself, etc.
Going to change the kor file after review.
In order to properly type an `Operation`, we need to change the call site from having two arguments: one for `type` and one for `payload` into an object that contains both. This isn't a perf regression because we were already constructing this object in the first place and doesn't change the emitted event so shouldn't affect the dev tools.
None of the call sites are actually flow-ified so it isn't technically used but once we will, it'll make sure that we don't send random strings and payload through those very generic methods.
React IDs have been killed and there was one call site left in a test. I trimmed down the implementation to keep only what is actually used and inlined it inside of the test so we don't get more people using it in the future.
* Type SimpleEventPlugin and TapEventPlugin
- Renamed file from 'ReactSynteticEvent' to 'ReactSyntheticEventType'
- Fills in the 'any' holes that were left in DispatchConfig type and the
type annotations in EventPluginRegistry.
- Adds polymorphic PluginModule type and related types
- Uses hack to support indexable properties on 'Touch' type in
TapEventPlugin
The issue in TapEventPlugin is that the code is accessing one of four
possible properties on the 'Touch' type native event using the bracket
accessor. Classes in Flow don't support using the bracket accessor,
unless you use a declaration and the syntax `[key: Type]: Type`.[1] The
downside of using that here is that we create a global type, which we
may not need in other files.
[1]: https://github.com/facebook/flow/issues/1323
Other options:
- Use looser typing or a '@FixMe' comment and open an issue with Flow to
support indexing on regular classes.
- Rewrite TapEventPlugin to not use the bracket accessor on 'Touch'. I
thought the current implementation was elegant and didn't want to
change it. But we could do something like this:
```
if (nativeEvent.pageX || nativeEvent.pageY) {
return axis.page === 'pageX' ? nativeEvent.pageX : nativeEvent.pageY;
} else {
var clientAxis = axis.client === 'clientX' ? nativeEvent.clientX : nativeEvent.clientY;
return nativeEvent[axis.client] + ViewportMetrics[axis.envScroll];
}
```
It turns out that flow cannot type `this` with a function constructor + prototype overrides. Turning it to a class makes flow happy and has minimal impact on the output.
In open source, we already use the loose version of the class transform and internally we have one that's outputting even less code if you have `@preventMunge` in the header.
See discussion in https://www.facebook.com/groups/2003630259862046/permalink/2098480820376989/
We disabled coverage in Travis because the implementation was crashing ( https://github.com/facebook/react/issues/6290 ). Since we upgraded to Jest 15, the entire coverage implementation is brand new so we should give it another try.
This commit takes the first incremental step towards adding type checks
to the React event code. A couple of issues came up.
There is an issue with the SyntheticEvent type: Flow declares a
SyntheticEvent type[1] that lacks the non-public properties which are
used in React internals. To solve this I declared a class that extends
SyntheticEvent. This class can be expanded as we add Flow types to more
places where SyntheticEvent instances are referenced.
I'm happy to change this if folks prefer a different approach.
Some options I considered:
- Override the SyntheticEvent declaration with our own declaration
- Pro: We can use 'SyntheticEvent' as a type just like we are used to
when working in any other codebase.
- Pro: No need to import any type since it's a declaration
- Pro: Only one version of SyntheticEvent; less confusion.
- Con: Could get out of sync with real implementation.
- Con: Duplicates part of the type declared in Flow.
- Import the SyntheticEvent class and use that as the type
- Pro: Keeps type definition in sync with the real implementation.
- Con: Declaration overrides implementation so I'm not sure this would
work.
- Con: Have to remember to import the type.
- Declare a separate type called ReactSyntheticEvent that extends
SyntheticEvent
- Pro: Stays in sync with the Flow SyntheticEvent type;
less duplication.
- Pro: Differentiates this type from the Flow SyntheticEvent type;
less confusion.
- Pro: No need to import any type since it's a declaration
- Con: Could get out of sync with real implementation.
I also ran into an issue where a variable was only non-null when
'__DEV__' is true, similar to PR #7586.[2] The work-around is to force
it to be typed non-null and add a comment documenting the reason. At
this time Flow doesn't have a better way to deal with the situation.
Next steps:
- Specific type for the 'dispatchConfig' property of SyntheticEvent
- More detailed types for PluginName and PluginModule
Lastly; note that I renamed some variables to follow the convention of
reserving PascalCase for classes, enums, and Flow types.
[1]: https://github.com/facebook/flow/blob/master/lib/react.js#L277-L293
[2]: b99eb5087b
We used to copy and paste the same big blob many times in order for it to work with keyOf which is no longer a constraint. This pull request takes a list of all the events as string and generate those data structures at runtime.
It reduces the size of React by 1k post gzip and flow is able to extract the structure out of it :)
Jest 15 has just been released and is way more awesome: http://facebook.github.io/jest/blog/2016/09/01/jest-15.html
This pull request updates jest from version 12 to 15. Right now there's a fix in jest around Symbol that hasn't been released yet, so this will break CI and cannot be merged it. But once it ships by the end of the day, we'll be good to go :)
See comments inline for all the changes I've done.
This is the last callsite of keyMirror! It removes 0.5k gzipped :)
The only trick with this one is that ReactTestUtils actually iterates over the list of all the events. Instead of duplicating the logic, I used the $Enum feature of flow that lets us statically extract out the type from the dynamic value. Inside of react-dom we're no longer requiring the file directly so it doesn't bloat the file size, and we still get to have static typing, best of both worlds!
This one is interesting because we have transaction objects being passed around everywhere in the codebase but there's actually no Transaction class. It's a "mixin" that comes to life by being Object.assigned to the prototype of a real "class" (before class was cool!). Therefore, we can't just say `var Transaction = require('Transaction'); (transaction: Transaction) => { }` because it would be the object that contains a mixin and not an instance of a transaction.
The trick I use is to export `TransactionType` and alias it to `Transaction` in the file as it doesn't actually require transaction. In case they do, we'll figure it out, but in the few files I looked at, it doesn't seem to be the case.
For the perform function, it actually typechecks pretty well!
This one was really interesting to type as it's doing a lot of unusual JavaScript. Fortunately flow is now pretty kick ass and I've been able to mostly type it. The only missing piece is that it won't check the constructor arguments.
If you are a fb employee, you can follow the discussion here: https://www.facebook.com/groups/flowtype/permalink/1132359430146004/
Incrementally type ReactInstance by adding the types of attach/detachRef.
I moved isValidOwner as a function inside of the file since it's never used externally.
This one involves a bit more work as I added "phantom" flow types to a bunch of places where the type is a ReactPropTypeLocations even though those files are not `@flow` yet.
A good side effect is that `ReactPropTypeLocationNames` keys are now correctly typed, this means that they cannot go out of sync without breaking flow :)
Flow doesn't really support the concept of variables that are non-null but only inside of a `__DEV__` block. There's an internal post about it ( https://www.facebook.com/groups/flowtype/permalink/1132437726804841/ ) and the conclusion is that we should force it to be non-null and trust the developer to put the proper DEV checks in place.
We need to export FlushHistory type and I submitted a PR on flow to fix the type of console.table which is too restrictive.
I'm already starting to see the benefits of flow, I can look at random variables in the code and flow knows what shape the objects are! It's really useful to try and understand what's going on :)
In Type ReactComponentTreeHook #7504, I merged even though travis didn't report green (travis for all the fb repos has been backlogged like crazy since this morning) by manually doing `npm test` and `npm run flow` but I didn't ensure that lint was all green.
@millermedeiros pinged me about it so here's a quick fix
For this one, I wanted to type a non-trivial piece of the codebase and ran into the fact that we do not have types for ReactElement nor ReactInstance, so I had to create them.
I'll add comments inline
It used to be slow whenever a type miss occurred because expensive `Error` objects were being created. For example, with `oneOfType([number, data])`, passing a date would create an `Error` object in `number` typechecker for every item.
The savings depend on how much commonly you used `oneOfType()`, and how often it had “misses”. If you used it heavily, you might see 1.5x to 2x performance improvements in `__DEV__` after this fix.
* Write failing test
* Ensure .min and .max are set before .value
* Adjusting test for false negative
* Revert test adjustment (apparently it was only failing locally)
I already had to aliasify to have better control over the requires
so we might as well do it everywhere for consistency.
This probably makes it easier to rebase the rollup work too
because aliases seems to be how you solve this in that world.
This is needed for flat builds. It also lets us get rid of a bunch
of special cases in the build scripts.
It also allow us to just copy the source files into React Native
instead of having to build first to resolve the special cases.
* Remove onBeforeMountComponent hook event
It is unnecessary.
We now pass the element as part of onInstantiateComponent, and it can't change before mounting.
* Remove onComponentHasMounted hook event
It is unused after #7410.
* Replace on(Begin|End)ReconcilerTimer hook events
We already have onBeforeUpdateComponent.
Let's just have on(Before?)(Mount|Update|Unmount)Component and stick with them.
This removes double event dispatches in some hot spots.
* Remove onComponentHasUpdated hook
The tests still pass so presumably it was not necessary.
* Add missing __DEV__ to TestUtils code
* Replace on(InstantiateComponent|SetParent) with onBeforeMountComponent
This lets us further consolidate hooks.
The parent ID is now passed as an argument to onBeforeMountComponent() with the element.
* Remove onMountRootComponent hook event
It is unnecessary now that we pass the parent ID to onBeforeMountComponent.
* Use parentDebugID = 0 both for roots and production
This removes some awkward branching.
This builds a `react-dom-fiber.js` bundle which exposes ReactDOMFiber.
This allows early experiments with the new Fiber reconciler.
I also expose it in the npm package through `react-dom/fiber`.
This copies modules into three separate packages instead of
putting it all in React.
The overlap in shared and between renderers gets duplicated.
This allows the isomorphic package to stay minimal. It can also
be used as a direct dependency without much risk.
This also allow us to ship versions to each renderer independently
and we can ship renderers without updating the main react package
dependency.
We currently write all our tests against the DOM implementation.
I need a way to run the Fiber tests against it. But I don't want
to take on any package dependencies on Fiber modules yet.
There's a problem with jest right now where you can't globally
mock modules that already exist. So I have to add a global call
to jest.mock.
Luckily we already have a way to test the useCreateElement paths
using a feature flag. I won't activate this flag in travis until
it passes, but the idea is to run all three variants in travis.
I'm not sure that invoking rAF and rIC synchronously is the best
way to test this since it doesn't capture the backwards
compatibility aspect. I.e. the fact that people might be relying
on the synchronous nature in real apps too. It's a start.
Ideally, jest would have these built-in.
* Remove unnecessary indirection from the tree hook
* Replace onSetDisplayName, onSetOwner, onSetText with one event
Less events is better.
onSetDisplayName, onSetOwner, and onSetText only existed because we didn't initially track elements.
* Remove unused variables
* Prevent internal performance regression
This only affects Facebook website, not open source version of React.
On the Facebook website, we don't have a transform for warnings and invariants.
Therefore, expensive arguments will be calculated even if the warning doesn't fire.
This fixes a few cases where that calculation might be more expensive than usually.
In my testing, this brings down average row click time in Power Editor from ~300ms to ~220ms in __DEV__ (vs ~40ms in prod).
* Put warning() that shows up in profile behind condition
* corrected ReactChildrenMutationWarningHook's name
* changed `onComponentHasMounted` to `onMountComponent`
and get element from `ReactComponentTreeHook` instead of keeping an internal store
Without this we end up bundling all of the isomorphic React into
the DOM bundle. This was fixed in #7168 too but I'll just do an
early fix to ensure that #7168 is purely an npm change.
* Cut out isomorphic dependencies from the renderers
These files reaches into isomorphic files.
The ReactElement functions are exposed on the React object anyway
so I can just use those instead.
I also found some files that are not shared that should be in
renderers shared.
* Found a few more shared dependencies
renderSubtreeIntoContainer is only used by the DOM renderer.
It's not an addon.
ReactClass isn't needed as a dependency since injection doesn't
happen anymore.
* Use a shim file to load addons' dependencies on DOM
By replacing this intermediate file we can do the lazy loading
without needing any lazy requires. This set up works with ES
modules.
We could also replace the globalShim thing with aliased files
instead for consistency.
* Bundle DOM renderers into their individual UMD bundles
Instead of exposing the entire DOM renderer on the react.js
package, I only expose CurrentOwner and ComponentTreeDevtool which
are currently the only two modules that share __state__ with the
renderers.
Then I package each renderer in its own package. That could allow
us to drop more server dependencies from the client package. It
will also allow us to ship fiber as a separate renderer.
Unminified DEV after before
react.js 123kb 696kb
react-with-addons.js 227kb 774kb
react-dom.js 668kb 1kb
react-dom-server.js 638kb 1kb
Minified PROD after before
react.min.js 24kb 154kb
react-with-addons.min.js 37kb 166kb
react-dom.min.js 149kb 1kb
react-dom-server.min.js 144kb 1kb
The total size for react.min.js + react-dom.min.js is +19kb larger
because of the overlap between them right now. I'd like to see
what an optimizing compiler can do to this. Some of that is fbjs
stuff. There shouldn't need to be that much overlap so that's
something we can hunt. We should keep isomorphic absolutely
minimal so there's no reason for other React clones not to use it.
There will be less overlap with Fiber.
However, another strategy that we could do is package the
isomorphic package into each renderer bundle and conditionally
initialize it if it hasn't already been initialized. That way
you only pay an overlap tax when there are two renderers on the
page but not without it. It's also easier to just pull in one
package. The downside is the versioning stuff that the separate
npm package would solve. That applies to CDNs as well.
ReactWithAddons is a bit weird because it is packaged into the
isomorphic package but has a bunch of DOM dependencies. So we have
to load them lazily since the DOM package gets initialized after.
This took a while to figure out, but we need to be able to store
children that are currently being worked on separately from the
current children. We always need a canonical "current" children
so that we can update them. However, we also need a different set
that we're currently working on so that we have a way to get to
already progressed work.
This solve the starvation problem in the first render because now
we can reach children that were never rendered and have a place
to store their progressed work on. The unit test changes tests
this.
This lets us get rid of the hasWorkInProgress flag.
When we reconcile new children we need to reconcile them against
progressed work so that we can reuse it. The progressed work is
"work in progress" nodes. So in that case we need to mutate
instead of clone, to preserve the invariant that only two versions
exist at any given point. This effectively forks the
ReactChildFiber implementation.
We need to use the *other* child because we reset it to the
current one on the way up.
We also need to reset the first/last side-effects to that of the
children so that we're committing the right thing.
Thanks @acdlite. Add comment about future unit test coverage.
This was actually hiding the fact that we are only able to reuse
existing work if it was marked as completely finished which it
won't be if we reuse its pending priority.
However, we should be able to bail out even if there is work
remaining in a subtree.
When we downprioritize children we need to remember to reuse the
old children in the update side-effect.
This whole set up is very unfortunate since we can have children
in our active tree that never actually finished rendering. This
strategy might be fundamentally flawed, not sure.
This might become confusing later but is unreachable today. That's
because existing pendingProps only matter when a clone is updated,
but this path can only matter when it is created.
If the current work is higher priority than the new work, then
don't bother resetting the unit of work pointer since it won't
affect the execution order.
I'm paranoid about inline-ability so I use this pattern of adding
a constant to the closure everywhere.
ES6 modules help avoid that but we can't use that consistently
because of the dependency injection so instead I opt for making
this explicit everywhere.
Grep: \b[a-zA-Z_$\d]+\.[a-zA-Z_$\d]+\(
'change' custom events raise "Member not found" in <= IE10. To
circumvent this, the SyntheticEvent class now checks for "typeof
event.cancelBubble !== 'unknown'". This eliminates this exception and
maintains the expected bubbling functionality.
Addresses #7320.
* PropTypes: distinguish nullable from optional object field
This gives a more precise message (no type semantics change) to the case of passing a field in an object, but whose value is `null`:
Before:
```js
propTypes: {
foo: React.PropTypes.number.isRequired
}
```
Would scream "Required prop `foo` was not specified in `MyComp`".
Now it'll be "Required prop `foo` was specified in `MyComp`, but its value is `null`.".
Works as expected in nested objects.
This fixes the issue of a component transitively passing a `null`, specifying the correct field to the child but have the child tell it that it didn't provide the prop.
Optional field and nullable are two different things anyway.
* Add missing test case.
* Reword messages.
For controlled inputs, `updateWrapper` was getting called before the
`type` prop had a chance to update. This could lead to a case where
switching from the `text` to `number` type caused a validation error
that would prevent the proper input value from being assigned.
This commit moves the call to `ReactDOMInput.updateWrapper` below
`_updateProperties` to avoid this situation.
"It is worth repeating: there is no configuration files or complicated folder structures." > "It is worth repeating: there are no configuration files or complicated folder structures."
- Reverts change to use sectionid on layouts (was unreliable), using config to make sure that's specified on all pages that need it
- Adds permalinks to all other pages so that og data is correct
- Corrects some permalinks that were in correct (translations)
* Eagerly evaluate inline requires in Jest
I inlined some requires in #7188 to fix the build size regression.
However this caused an issue with Jest due to it resetting module registry between tests.
This is a temporary fix to #7240.
It should be reverted as part of #7178.
* Make the hack work in all environments
Previously, the extract-components script would create the same number of layers of composites as the page it captures, but it would output a new class for each time any composite is used (since we don't want to replicate all the component logic).
I changed the script to output a single type for each type in the input -- and each generated component takes an index for which output it should return. This should be closer to how the original code behaves, especially with respect to VM function call lookups where the amount of polymorphism makes a difference.
I re-recorded the benchmarks with the new scripts. They run significantly faster:
```
Comparing old.txt (control) vs new.txt (test)
Significant differences marked by ***
% change from control to test, with 99% CIs:
* ssr_pe_cold_ms_jsc_jit
% change: -41.73% [-43.37%, -40.09%] ***
means: 39.3191 (control), 22.9127 (test)
* ssr_pe_cold_ms_jsc_nojit
% change: -44.24% [-46.69%, -41.80%] ***
means: 45.8646 (control), 25.5764 (test)
* ssr_pe_cold_ms_node
% change: -45.61% [-47.38%, -43.85%] ***
means: 90.1118 (control), 49.0116 (test)
```
This is probably in part due to the changes here, but also the page I captured has changed somewhat in the meantime and there seem to be slightly fewer components in the hierarchy, so they're not really comparable. But going forward we can use this benchmark which should be more accurate. I also included an identical copy that uses stateless functional components so we can test optimizations to those later.
As reported in #7227, unmounting performance regressed with React 15.
It seems that `delete` has become much slower since we started using numeric keys.
Forcing dictionary keys to start with a dot fixes the issue.
* Add failing test demonstrating a ReactPerf warning
* Make the failing ReactPerf test more precise
* Make ReactPerf.start() work during reconciliation
* Reorder lifecycle methods for greater clarity
* Fix memory leak
* Error boundaries should not break ReactPerf
* Put onBeginFlush/onEndFlush into transaction wrappers
This looks cleaner even though it is not strictly necessary.
We still call them manually for unmounting because it doesn't have a transaction.
This provides an easy way to indicate that components should only rerender when given new props, like PureRenderMixin. If you rely on mutation in your React components, you can continue to use `React.Component`.
Inheriting from `React.PureComponent` indicates to React that your component doesn't need to rerender when the props are unchanged. We'll compare the old and new props before each render and short-circuit if they're unchanged. It's like an automatic shouldComponentUpdate.
* Add failing tests for #7187 and #7190
* Pass shouldHaveDebugID flag to instantiateComponent
This allows us to remove a hack that was added in #6770 and caused #7187 and #7190.
* Move logic for choosing whether to use debugID outside instantiate
Touch behavior is inconsistent across different platforms, and ResponderTouchHistoryStore currently fatals when assumptions are broken. In addition, the behavior differs between development and production.
This pull request does a few things to make ResponderTouchHistoryStore easier to deal with:
Adds Flow to keep the TouchEvent, Touch, and TouchRecord types straight.
Changes behavior to be consistent across environments. This means either always throwing or never throwing (and making use of warning and console.error as appropriate).
When an orphaned move or end event is received, print debug information and ignore it instead of crashing and burning.
* Warn if PropType function is called in production
* Check if console is undefined before warning
* Randomize value of ReactPropTypesSecret
* Remove dev environment tests
* Rename typeCheckPass to productionWarningCheck
* Rename productionWarningCheck to expectWarningInProduction
* Call toString on Math.random()
* Rename test block for React type checks
* Make sure warning isnt emitted for failing props
* Cache warning by component and prop, warn in dev
* Pass ReactPropTypesSecret to internal checks
* Move tests to ReactPropTypes-test.js
* Update the warning message to include link
* Do not test warning for unions with invalid args
Summary:
I had to cast into any because flow doesn't think that checking the lowercase version of nodeName is a valid way to refine the variable from HTMLElement to HTMLInputElement. I'm also not confident enough in changing the implementation to an instanceof HTMLInputElement to please flow. It also takes care of the null check in the process.
The `nodeName &&` condition wasn't useful since the two branches are checking it against concrete values and actually makes the type different since nodeName is not a boolean per se. I replaced them with if conditions to make it clearer what it actually did instead of doing boolean logic tricks.
It is unclear why I had to type supportedInputTypes, see this internal post for a discussion: https://www.facebook.com/groups/flowtype/permalink/1084168611631753/
The only difference in behavior is that I now explicitely convert to boolean the object dereference via `!!`.
Test Plan:
npm run flow
Careful inspection of the code
Reviewers: @zpao @spicyj
* Inline dev-only requires
This reduces the production bundled build size.
* Use new references after resetting module registry in tests
This fixes the tests which were broken due to inlining some requires.
This commit fixes#5473: ReactDOMServer.renderToString: presence of onClick
handler causes errors on async update
This commit performs the following changes:
- Adds a getUpdateQueue method to ReactServerRenderingTransaction,
ReactReconcileTransaction, ReactNativeReconcileTransaction and
ReactTestReconcileTransaction
- Make the ReactCompositeComponent call this getUpdateQueue instead of using
ReactUpdateQueue that was unwanted at certain moments on server
- On ReactServerRenderingTransaction, dispatch ReactUpdateQueue's methods
while rendering and warning methods afterwards. This is done through the new
ReactServerUpdateQueue class
- Added a series of tests that mimics the case presented in #5473 with setState,
forceUpdate and replaceState
- Add flow typechecking on concerned files
- Removed the prop transitionAppearTimeout from
addons/transitions/ReactTransitionGroup in order to remove a warning
when passing unknown props to DOM elements.
This is only for host nodes so that the DOM tree is fully updated
by the time we've flushed.
Classes will schedule their life-cycles *after* their children's
side-effects.
This creates a new API for processing side-effects on the host
environment.
During initial reconciliation host instances are created during
the time sliced periods.
During updates there is an opportunity for the host
to prepare something on the instance during the time slicing, and
to determine whether there were any changes. The could be thrown
away.
At the commit phase, these changes are finally committed to the
host instance.
This adds tracking of side-effects that gets scheduled during an
update.
As the tree gets reconciled, the side-effectful fibers are linked
together in an ordered singly linked list. That way we can walk
the linked list to commit only the work that needs to be
synchronous - quickly.
We also store first and last nodes within a fiber. That
way when we reuse an already processed subtree, we can reuse that
subset of the linked list.
This is not just the parent Instance but also the return Fiber for
some piece of work. This clarifies and buys into this definition.
Basically, in the current model you will always pass into a fiber
from the parent that you're going to return to. Even if you get
aborted and reused this will be updated to the correct return
fiber before you get back here.
I don't have any guarantees in place to enforce this right now. I
don't really know how to, but seems safe. :)
I confirmed that the use of keyword properties work for old
engines because we have the transform enabled in our build system.
This tries to reuse work that was completed but another higher
priority event came in. This tries to avoid starvation when high
priority events causes low pri work to keep rerendering from
scratch.
First I fix a bug where host components didn't properly bail out
although this was unobservable.
When we bail out, we need to ensure that we preserve the highest
remaining priority work that is left to do for that subtree.
This still isn't properly handling the case when that work has the
*same* priority as the current one. That work will be flushed the
*next* tick instead of the current pass.
I can't create a test for that yet since I need setState to get to
that state.
This fixes some bugs with the clones and traversing backwards
through them. It is important that we maintain the correct parent
at all times and that clones have the correct values.
We need to carefully clone everything on the way up to the the
fiber with the next work to do.
This code is a bit messy and fragile now. I'm sure I didn't get it
all right but I want to get the basics in place first. Then we can
structure this part better. I think the general algorithm is sound
though.
We need a canonical stateful root for each. I don't really want to
overload the HostContainer for this purpose since it makes the
fiber code more specialized.
Instead I create a root which represents an actual stateful root.
When these get scheduled they get chained together in a linked
list. However, we don't hold onto anything that doesn't have
scheduled work. This will help us release everything automatically
in the GC, as long as there are no subscriptions nor scheduled
work.
This is a bit poorly structured. I'll restructure when the pieces
are better in place.
Basically we reset the priority of a node before work on the
children. The children then bump their parent if they end up
having work left.
This is the first time we're seeing deep updates happening. The
new unit test demonstrates this.
There is an interesting case that happens when we fall back out of
a deep update. We end up "completing" a node that we didn't begin.
This probably breaks in coroutines. When that completes, it'll try
to render the sibling next but that should bail out so we check
for any pending work on the sibling. That one I'm not sure about.
This is essentially equivalent to the current top level wrappers.
They contain the next children to be mounted into a container node
from the host.
It is the responsibility of the host to retain references to them
for updates.
I expect them to be able to exist in the middle of the tree in
the future, for renderSubtreeIntoContainer.
This flag on fibers will be used to track what priority of work is
needed by that subtree, if any at all.
Also fix up the TypeOfWork to have consistent naming and typing.
* Fix for 5468: Validate proptype definitions sooner
Added typeCheckWarn() func and updated the oneOf/oneOfType tests
Added __DEV__ warning for invalid oneOf/OneOfType args
* Suppress redundant error on warn; typeCheckWarn() removed
* Return no-op
* Using emptyFunction module for consistency
* Remove createChainableTypeChecker() call
* Adjust test to assert type check passes when warned
* create failing test case
* Fix renderSubtreeIntoContainer to update context
Fixes#6599
* Also test re-rendering due to prop update
* Address review feedback
This was added to catch internal errors in React but doesn't seem to be doing much good except frustrating people more when their apps throw (#6895, FB-internal t11950821). Until more proper error boundaries land, let's make this a warning.
Although it is unreasonable to set every possible property for
simulated events, `type` is useful for event handlers that are shared
between types and potentially have different behaviors.
* Resolve refs in the order of the children
React makes no guarantees about ref resolution order. Unfortunately, some of the internal Facebook component APIs (specifically, layer dialogs) currently depend on the ref resolution order. Specifically, the assumption is that if the layer dialog is placed as a last child, by the time it mounts or updates, the refs to any previously declared elements have been resolved.
With the current `ReactMultiChild`, this is *usually* the case but not always. Both initial mount and an update of all components satisfy this assumption: by the time a child mounts or updates, the previous children’s refs have been resolved. The one scenario where it isn’t true is when **a new child is mounted during an update**.
In this case, the `mountComponent()` call used to be delayed until `ReactMultiChild` processes the queue. However, this is inconsistent with how updates normally work: unlike mounting, updating and unmounting happens inside `ReactChildReconciler.updateChildren()` loop.
This PR changes the `mountComponent()` to be performed inside `ReactChildReconciler`, just like `receiveComponent()` and `unmountComponent()`, and thus ensures that `attachRef()` calls are enqueued in the order the children were processed, so by the time the next child flushes, the refs of the previous children have been resolved.
This is not ideal and will probably be broken by incremental reconciler in the future. However, since we are trying to get rid of mixins in the internal codebase, and layered components are one of the biggest blockers to that, it’s lesser evil to temporarily make ref resolution order more strict until we have time to fix up the layer APIs to not rely on it, and are able to relax it again (which would be a breaking change).
* Use array instead of object to avoid lookups
Summary:
The only callsite of ReactStateSetters is in LinkedStateMixin which lives in addons/link. Better move it there to avoid cluttering the other folder.
Test Plan:
None
Reviewers: @zpao @spicyj
Summary:
The only callsite left was removed here: e8af100849 (commitcomment-17570210) but the code to handle it remained.
Test Plan:
tbgs and ibgs, make sure there's no callsites.
Reviewers: @jimfb, @spicyj, @sebmarkbage
* Standardise format of the three "state" questions.
The original format follows the template:
> 1. x? if `x` then probably isn't state
> 2. y? if `!y` then probably isn't state
> 3. z? if `z` then it's not state
This caused both me and a hallway tester to do a double take.
The proposed reformulation allows the answers to follow the same template.
In the same spirit, it uses the same contraction pattern in the last answer (`it's not state`-> `it isn't state`). This has the welcome side effect to make the lack of "probably" stand out more.
* Update phrasing in thinking in reacr
Summary:
Trying to start adding flow types to files in React. I needed to add a script to package.json in order to run flow, flow-bin is already a dependency.
I had to rewrite the implementation a bit. Flow doesn't recognize
```
var currentIsArray = Array.isArray(current);
if (currentIsArray) {
// not refined
}
```
but the following does work
```
if (Array.isArray(current)) {
// refined
}
```
Test Plan:
npm run-script flow
npm run-script test accumulate
Reviewers: @zpao @spicyj
* Workaround IE lacking innerHTML on SVG elements
* Add tests for setInnerHTML
* Correctly check if node has innerHTML property
* Ensure tests for setInnerHTML actually tests both codepaths
* Provide mock element for setInnerHTML tests
* Only use SVG setInnerHTML workaround for SVG elements
This avoids using .alternate as much as possible and isolates it
to the root. For anything that is "work in progress" this happens
to be the same as the alternate field. To avoid an extra "current"
field on work in progress fibers, we can just use the alternate.
The timing for when this is true might be a bit tricky to reason
about so I explicitly pass the current value everywhere from the
top. That way we can always change this in the future to use an
explicit field or we can try to maintain a parallel data
structure that remembers which was the "current" fiber for each
wip child.
These values represent fibers that are incomplete. In the current
model they're mutated in place. In a completely immutable model
they would need to be cloned for every step they make progress.
I.e. one where the child is still in this WIP state and one when
it is complete.
To clarify this I'll name them workInProgress while they're in
that state, which is also what Jordan did in his prototype.
This splits the Fiber type into Fiber and Instance. This could be
two different object instances to save memory. However, to avoid
GC thrash I merge them into one.
When ReactChildFiber reconciles children, it clones the previous
fiber. This creates a new tree for work-in-progress. The idea is
that once flushed, this new tree will be used at the root.
However, we know that we'll never need more than two trees
at a time. Therefore my clone function stores the clone on the
original. Effectively this creates a fiber pool.
Ideally, the .alternate field shouldn't be used outside of clone
so that everything can work with pure immutability. I cheat a bit
for now so I don't have to pass both trees everywhere.
ReactChildFiber is a bit hacky for reuse and doesn't solve all
cases. Will fix that once I try to get parity.
Also ignore examples, important because react can be installed by the commonjs
one and the modules will get detected there too, resulting in duplicate
definitions
Most people don't use the official Flux implementation or docs so I think this is likely to be more confusing than helpful. Maybe later we can add a better comparison of data management solutions.
This gets rid of a field that we only need for coroutines.
We might need this if we have multi phase handlers in the future
but then maybe we can just use multiple tags.
This has a few benefits:
1) This allows the element to always remain on the young generation.
2) The key can be accessed on the fiber which is easier to keep as the
same class and is directly accessible in the child reconciliation of every
object.
3) This conveniently means that we don't have to create a fake element for
continuations which was really hacky.
We can still do the quick bailout of rerendered things using the props
object which is also unique.
We don’t want to have different behavior in development and production.
Previously, we used to ignore getters on key/ref in dev, but we’d read them in prod.
Now, we only ignore the getters that we *know* we created so the production logic doesn’t differ.
This way in other cases both DEV and PROD falls through to the check for undefined.
This fixes#6879 and a similar bug introduced for cloneElement() in 94d0dc68c8.
It currently fails in `createElement` because of #6879 which was introduced in #5744.
It also fails in `cloneElement` because the code with that bug was extracted and shared in 94d0dc68c8.
Previously, this threw:
```
FAIL src/test/__tests__/ReactTestUtils-test.js (7.291s)
● ReactTestUtils › it can fail context when shallowly rendering
- TypeError: Cannot read property '_source' of null
at describeID (src/renderers/shared/devtools/ReactComponentTreeDevtool.js:70:46)
at Object.ReactComponentTreeDevtool.getStackAddendumByID (src/renderers/shared/devtools/ReactComponentTreeDevtool.js:203:15)
at checkReactTypeSpec (src/isomorphic/classic/types/checkReactTypeSpec.js:76:58)
at ReactCompositeComponentMixin._checkContextTypes (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:668:5)
at ReactCompositeComponentMixin._processContext (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:607:14)
at ReactCompositeComponentMixin.mountComponent (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:191:30)
at ReactShallowRenderer._render (src/test/ReactTestUtils.js:483:14)
at _batchedRender (src/test/ReactTestUtils.js:460:12)
at ReactDefaultBatchingStrategyTransaction.Mixin.perform (src/shared/utils/Transaction.js:140:20)
at Object.ReactDefaultBatchingStrategy.batchedUpdates (src/renderers/shared/stack/reconciler/ReactDefaultBatchingStrategy.js:65:19)
at Object.batchedUpdates (src/renderers/shared/stack/reconciler/ReactUpdates.js:112:20)
at ReactShallowRenderer.render (src/test/ReactTestUtils.js:453:16)
at Spec.eval (src/test/__tests__/ReactTestUtils-test.js:289:34)
at jasmine.Block.execute (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:1067:17)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2100:31)
at jasmine.Queue.start (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2053:8)
at Spec.jasmine.Spec.execute (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2380:14)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2100:31)
at onComplete (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2096:18)
at Spec.jasmine.Spec.finish (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2354:5)
at eval [as onComplete] (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2381:10)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2110:14)
at eval (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2090:18)
at Timeout.e [as _onTimeout] (node_modules/jsdom/lib/jsdom/browser/Window.js:440:19)
at tryOnTimeout (timers.js:224:11)
at Timer.listOnTimeout (timers.js:198:5)
```
* Don't count the time inside flushes towards lifecycle hooks
Fixes#6842.
We keep the existing behavior of testing for matching `onBeginLifeCycleTimer`/`onEndLifeCycleTimer` calls, but we push the current timer onto the stack if we enter a flush.
This solves an issue with portals which cause updates while a lifecycle timer is already running.
I chose to subtract the time spent in the flush from the time counted towards the lifecycle method because it would artificially inflate the “total” time of the component due to all the components inside the portal, so it would skew the exclusive table.
* Fix up the comment
This helps us make sure we don't break React ART in a minor or patch release. The idea is to not change these files when making minor or patch changes. Copied directly from react-art with requires fixed. (I also picked a different haste name just in case.)
* Fix componentWillUnmount() not counted by ReactPerf
* Test that functional component render() time shows up in ReactPerf
* Test for setState() code path updates being included
* Update shallowCompare to accept nextContext
Across our application we are using immutable objects as properties and thus using shallowCompare for all our {{shouldComponentUpdate}}. Because of this children with contextTypes don't get updates when the context on the parent changes. Adding an additional comparison for context (when it is provided) fixes this problem.
* Remove the undefined check
* Add nextContext
This adds some tests for getElement() and verifies that it works for text components too.
The code that calls the instrumentation is fixed where necessary so that the tests pass.
We extract common logic between DOM and native tests so they don't diverge.
Also, rather than build a tree object in advance for testing, we will walk the tree on the go.
This lets us have much more specific error messages with a clear path when something goes wrong.
Test Plan: Changed the preprocessor to log the output of babel.transform and saw
```
var _jsxFileName = 'src/isomorphic/modern/element/__tests__/ReactJSXElementValidator-test.js';
```
in the resulting output, instead of an absolute path.
One of the ReactMultiChildText tests renders 2145 roots (and even more components) and unmounts none of them. Now we don't loop through them all a bunch of times so the test takes 20 seconds instead of 60.
We should clean up instantiateReactComponent somehow so that the onSetDisplayName call isn't produced for the TopLevelWrapper, which should allow us to just store an array of unmountedIDs instead of a hash map so we at least don't have double maps. This change mirrors the old logic though.
Reviewers: @gaearon, @sebmarkbage
Being able to get the source for your parent components seems useful, and ReactComponentTreeDevtool is best poised to be able to do that.
I'm also not sure it makes sense to have separate DOM-specific `onMountDOMComponent` and `onUpdateDOMComponent` events, so I removed them for now. Even if we want them, their timing seemed sort of arbitrary.
I also made it so DOM devtools can listen to non-DOM events too. Willing to change that if people think it's ugly though.
I *think* this should refer to the second example, where the instance to the ref is stored. In any case please can someone confirm for my own understanding?
For clarity.
I left "native event" as-is because there's a lot of it, it's not particularly ambiguous, and SimulateNative/nativeTouchData are public API in ReactTestUtils.
`ReactDebugTool` used to only call `purgeUnmountedComponents()` while profiling, so information about unmounted instances kept accumulating when not profiling.
Additionally, unmounting in React Native and rendering to string did not correctly clean up the devtool.
Finally, the tests tested the wrong behavior and relied on explicit `purgeUnmountedComponent()` calls.
To fix this, we:
* Test specifically that unmounting is enough to clean up the tree devtool.
* Add missing `onBeginFlush` and `onEndFlush` calls to server and native rendering so `ReactDebugTool` knows when to copy the tree.
Fixes#6750
This is an outline for the new reconciler infrastructure.
I created a noop renderer to have something to get started from.
I split the reconciler folder into old and new, as well as shared.
I put shouldUpdateReactComponent in shared as an example of a
utility that can easily be shared between both. I plan on breaking
out more utilities like these.
* New approach for 6062 fix : Show source line number on unknown property warning
* WIP: ReactDebugToolEventForwarderDevTool
* Update event signature to debugID
* Trigger events in ReactDOMComponent
* Renamed to onMountDOMComponent; passing in element directly
* Added debugID; updated simple test
* Added test for multi-div JSX to ref exact line
* Added test for composite component
This just configures flow to be checked and fixes our existing
Flow typed files.
Possible enhancements:
Export .js.flow declarations from the build. Unclear whether this
will be a supported workflow in the future or not, so let's wait
on that.
We should fail builds and CI on Flow errors.
Ideally we should lint for Flow style guides (like no space before
colon).
Technically this shouldn't happen but it seems possible with ReactNativeMount.unmountComponentAtNode().
For now, let's just ignore these lifecycle events because ReactPerf makes a hard assumption that all lifecycle hooks happen inside batches.
We can revisit later when we have a comprehensive test suite for ReactPerf itself.
This makes it easier to figure out where the docs live.
Googling for e.g. `react-addons-update` also works, but this should
make things easier for people that hyperclick directly to the source.
This is no longer needed on the native side.
This is also the last use of the Platform flag. React Core is now
platform agnostic with regard to React Native. So I'll remove
the mocks and dependency.
* Create 01-why-react.zh-TW.md
Translation for language code [zh-TW](https://en.wikipedia.org/wiki/Zh-TW)
* Update 01-why-react.zh-TW.md
change "封裝性非常好" to "封裝性高"
The current warning condition caused the first error to be swallowed, and all the next errors to be logged. I believe the intention was the opposite: to log the first error, and to ignore any next errors for the same method.
This can happen if something gets unmounted before the event gets
dispatched. I'm not sure how this works out exactly but this
preserves previous behavior in this scenario.
This fixes an issue where handling events on a node that was just removed threw a "All native instances should have a tag." error and matches what we do in the DOM renderer in ReactEventListener.
This isn't actually used right now so I can't test it. Because the
Chrome devtools are broken for React Native. The Nuclide integration
is in the react-native repo.
Our module rewrite whitelist needs to ignore providesModule files
that are going to be required from the global React Native
environment.
We also need to add ReactDOM to providesModule since we removed it
from React Native.
Moving the event plugins into their dedicated folder
Removing the ExecutionEnvironment override. I will just have to fix where needed. Probably related to the Chrome debugger?
* Only fire input value change events when the value changes
fixes#554, fixes#1471, fixes#2185 (still trying to figure out why)
* catch programmatic value changes
* move value tracking to seperate module
- Use correct "Note" formatting so they render correctly
- reordered sections so Node is first
- Use "Node.js" consistently (it is a product name just like Nashorn)
- added/tweaked some of the text
- simplified the Java code so it doesn't hit the internet.
ReactDOMInput and a few other classes handle change event by scheduling updateWrapper() in an asap().
It gets executed after the batch, which confuses ReactPerf that expects all DOM writes to happen during a batch.
Since this implementation of ReactPerf relying on the stack is going away, let's plug the hole temporarily by ignoring DOM writes that occur during postponed updateWrapper(). In any case, they have no relation to actual calculations of wasted renders, as they don't occur due to updateComponent(), but rather due to onChange() special DOM behavior.
This fixes#5548
This commit migrates over the disabled property behavior from
ReactDOMButton into a general purpose disabled event filter. It also
applies that behavior to inputs, selects, and textareas.
Since "This" is the subject and singular, "have" should be "has"
New wording explaining implementation details
Grammar fix for 15.0 blog post
Since "This" is the subject and singular, "have" should be "has"
Fix wording for 15.0 blog post
nitpicks
There seems to be a bug with medikoo/es6-symbol where the global state
affects the implementation of the polyfill. I found this by running the
individual test file alone then running all the tests using `grunt
test`. I found that it passes when ran alone and failed when ran
collectively.
I did not find this buggy behavior with zloirock/core-js's
implementation of a polyfill for Symbol. Thus, removing I will keep the
more popular polyfill (core-js) and remove the buggy polyfill
(es6-symbol).
If you are reading this and can think of a confounding factor that is
causing this bug, please let me know and we can try to work together to
add support for medikoo/es6-symbol.
Let's get more specific with our tests. Symbol has to be a function if
it's a polyfill. There are no object polyfills out there. (If there is,
ping me and I'll add support)
Instead of checking if Symbol is undefined, let's check if it's a
function instead since instanceof is depending that Symbol is already a
function.
1) If it is a native Symbol
2) If it is spec-compliant
3) Try to match non-spec compliant polyfill by a instanceof check on Symbol if it exists in the global namespace
Most ES6 polyfills will add support by implementing `Symbol` as a
function. This causes `typeof` to return `function` rather than `symbol`
for polyfilled clients.
With the edition of ECMA-262, we now have a new primative type called
Symbol. This primative type should be added to the PropTypes, as users
will eventually be using Symbols in their props for describing unique
and immutable data, such as identifiers.
Dev builds wrap synthetic events inside other events for a better debug
experience. However IE/Edge won't allow access to the
DataTransfer.dropEffect property if it's wrapped in this way.
The first time a drag event is fired, test if we're in an environment
that behaves this way and disable React's improved development
experience if we are.
**Do you want to request a *feature* or report a *bug*?**
**What is the current behavior?**
**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/reactjs/69z2wepo/).**
**What is the expected behavior?**
**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
* Fixed build issues with the Brunch bundler. ([@gaearon](https://github.com/gaearon) in [#8686](https://github.com/facebook/react/pull/8686))
* Improved error messages for invalid element types. ([@spicyj](https://github.com/spicyj) in [#8612](https://github.com/facebook/react/pull/8612))
* Removed a warning about `getInitialState` when `this.state` is set. ([@bvaughn](https://github.com/bvaughn) in [#8594](https://github.com/facebook/react/pull/8594))
* Removed some dead code. ([@diegomura](https://github.com/diegomura) in [#8050](https://github.com/facebook/react/pull/8050), [@dfrownfelter](https://github.com/dfrownfelter) in [#8597](https://github.com/facebook/react/pull/8597))
### React DOM
* Fixed a decimal point issue on uncontrolled number inputs. ([@nhunzaker](https://github.com/nhunzaker) in [#7750](https://github.com/facebook/react/pull/7750))
* Fixed rendering of textarea placeholder in IE11. ([@aweary](https://github.com/aweary) in [#8020](https://github.com/facebook/react/pull/8020))
* Worked around a script engine bug in IE9. ([@eoin](https://github.com/eoin) in [#8018](https://github.com/facebook/react/pull/8018))
### React Addons
* Fixed build issues in RequireJS and SystemJS environments. ([@gaearon](https://github.com/gaearon) in [#8686](https://github.com/facebook/react/pull/8686))
* Added missing package dependencies. ([@kweiberth](https://github.com/kweiberth) in [#8467](https://github.com/facebook/react/pull/8467))
## 15.4.1 (November 22, 2016)
### React
* Restructure variable assignment to work around a Rollup bug ([@gaearon](https://github.com/gaearon) in [#8384](https://github.com/facebook/react/pull/8384))
### React DOM
* Fixed event handling on disabled button elements ([@spicyj](https://github.com/spicyj) in [#8387](https://github.com/facebook/react/pull/8387))
* Fixed compatibility of browser build with AMD environments ([@zpao](https://github.com/zpao) in [#8374](https://github.com/facebook/react/pull/8374))
## 15.4.0 (November 16, 2016)
### React
* React package and browser build no longer "secretly" includes React DOM. ([@sebmarkbage](https://github.com/sebmarkbage) in [#7164](https://github.com/facebook/react/pull/7164) and [#7168](https://github.com/facebook/react/pull/7168))
* Required PropTypes now fail with specific messages for null and undefined. ([@chenglou](https://github.com/chenglou) in [#7291](https://github.com/facebook/react/pull/7291))
* Improved development performance by freezing children instead of copying. ([@keyanzhang](https://github.com/keyanzhang) in [#7455](https://github.com/facebook/react/pull/7455))
### React DOM
* Fixed occasional test failures when React DOM is used together with shallow renderer. ([@goatslacker](https://github.com/goatslacker) in [#8097](https://github.com/facebook/react/pull/8097))
* Added a warning for invalid `aria-` attributes. ([@jessebeach](https://github.com/jessebeach) in [#7744](https://github.com/facebook/react/pull/7744))
* Added a warning for using `autofocus` rather than `autoFocus`. ([@hkal](https://github.com/hkal) in [#7694](https://github.com/facebook/react/pull/7694))
* Removed an unnecessary warning about polyfilling `String.prototype.split`. ([@nhunzaker](https://github.com/nhunzaker) in [#7629](https://github.com/facebook/react/pull/7629))
* Clarified the warning about not calling PropTypes manually. ([@jedwards1211](https://github.com/jedwards1211) in [#7777](https://github.com/facebook/react/pull/7777))
* The unstable `batchedUpdates` API now passes the wrapped function's return value through. ([@bgnorlov](https://github.com/bgnorlov) in [#7444](https://github.com/facebook/react/pull/7444))
* Fixed a bug with updating text in IE 8. ([@mnpenner](https://github.com/mnpenner) in [#7832](https://github.com/facebook/react/pull/7832))
### React Perf
* When ReactPerf is started, you can now view the relative time spent in components as a chart in Chrome Timeline. ([@gaearon](https://github.com/gaearon) in [#7549](https://github.com/facebook/react/pull/7549))
### React Test Utils
* If you call `Simulate.click()` on a `<input disabled onClick={foo} />` then `foo` will get called whereas it didn't before. ([@nhunzaker](https://github.com/nhunzaker) in [#7642](https://github.com/facebook/react/pull/7642))
### React Test Renderer
* Due to packaging changes, it no longer crashes when imported together with React DOM in the same file. ([@sebmarkbage](https://github.com/sebmarkbage) in [#7164](https://github.com/facebook/react/pull/7164) and [#7168](https://github.com/facebook/react/pull/7168))
*`ReactTestRenderer.create()` now accepts `{createNodeMock: element => mock}` as an optional argument so you can mock refs with snapshot testing. ([@Aweary](https://github.com/Aweary) in [#7649](https://github.com/facebook/react/pull/7649), [#8261](https://github.com/facebook/react/pull/8261))
## 15.3.2 (September 19, 2016)
### React
- Remove plain object warning from React.createElement & React.cloneElement. ([@spudly](https://github.com/spudly) in [#7724](https://github.com/facebook/react/pull/7724))
### React DOM
- Add `playsInline` to supported HTML attributes. ([@reaperhulk](https://github.com/reaperhulk) in [#7519](https://github.com/facebook/react/pull/7519))
- Add `as` to supported HTML attributes. ([@kevinslin](https://github.com/kevinslin) in [#7582](https://github.com/facebook/react/pull/7582))
- Improve DOM nesting validation warning about whitespace. ([@spicyj](https://github.com/spicyj) in [#7515](https://github.com/facebook/react/pull/7515))
- Avoid "Member not found" exception in IE10 when calling `preventDefault()` in Synthetic Events. ([@g-palmer](https://github.com/g-palmer) in [#7411](https://github.com/facebook/react/pull/7411))
- Fix memory leak in `onSelect` implementation. ([@AgtLucas](https://github.com/AgtLucas) in [#7533](https://github.com/facebook/react/pull/7533))
- Improve robustness of `document.documentMode` checks to handle Google Tag Manager. ([@SchleyB](https://github.com/SchleyB) in [#7594](https://github.com/facebook/react/pull/7594))
- Add more cases to controlled inputs warning. ([@marcin-mazurek](https://github.com/marcin-mazurek) in [#7544](https://github.com/facebook/react/pull/7544))
- Handle case of popup blockers overriding `document.createEvent`. ([@Andarist](https://github.com/Andarist) in [#7621](https://github.com/facebook/react/pull/7621))
- Fix issue with `dangerouslySetInnerHTML` and SVG in Internet Explorer. ([@zpao](https://github.com/zpao) in [#7618](https://github.com/facebook/react/pull/7618))
- Improve handling of Japanese IME on Internet Explorer. ([@msmania](https://github.com/msmania) in [#7107](https://github.com/facebook/react/pull/7107))
### React Test Renderer
- Support error boundaries. ([@millermedeiros](https://github.com/millermedeiros) in [#7558](https://github.com/facebook/react/pull/7558), [#7569](https://github.com/facebook/react/pull/7569), [#7619](https://github.com/facebook/react/pull/7619))
- Skip null ref warning. ([@Aweary](https://github.com/Aweary) in [#7658](https://github.com/facebook/react/pull/7658))
### React Perf Add-on
- Ensure lifecycle timers are stopped on errors. ([@gaearon](https://github.com/gaearon) in [#7548](https://github.com/facebook/react/pull/7548))
## 15.3.1 (August 19, 2016)
### React
- Improve performance of development builds in various ways. ([@gaearon](https://github.com/gaearon) in [#7461](https://github.com/facebook/react/pull/7461), [#7463](https://github.com/facebook/react/pull/7463), [#7483](https://github.com/facebook/react/pull/7483), [#7488](https://github.com/facebook/react/pull/7488), [#7491](https://github.com/facebook/react/pull/7491), [#7510](https://github.com/facebook/react/pull/7510))
- Cleanup internal hooks to improve performance of development builds. ([@gaearon](https://github.com/gaearon) in [#7464](https://github.com/facebook/react/pull/7464), [#7472](https://github.com/facebook/react/pull/7472), [#7481](https://github.com/facebook/react/pull/7481), [#7496](https://github.com/facebook/react/pull/7496))
- Upgrade fbjs to pick up another performance improvement from [@gaearon](https://github.com/gaearon) for development builds. ([@zpao](https://github.com/zpao) in [#7532](https://github.com/facebook/react/pull/7532))
- Improve startup time of React in Node. ([@zertosh](https://github.com/zertosh) in [#7493](https://github.com/facebook/react/pull/7493))
- Improve error message of `React.Children.only`. ([@spicyj](https://github.com/spicyj) in [#7514](https://github.com/facebook/react/pull/7514))
### React DOM
- Avoid `<input>` validation warning from browsers when changing `type`. ([@nhunzaker](https://github.com/nhunzaker) in [#7333](https://github.com/facebook/react/pull/7333))
- Avoid "Member not found" exception in IE10 when calling `stopPropagation()` in Synthetic Events. ([@nhunzaker](https://github.com/nhunzaker) in [#7343](https://github.com/facebook/react/pull/7343))
- Fix issue resulting in inability to update some `<input>` elements in mobile browsers. ([@keyanzhang](https://github.com/keyanzhang) in [#7397](https://github.com/facebook/react/pull/7397))
- Fix memory leak in server rendering. ([@keyanzhang](https://github.com/keyanzhang) in [#7410](https://github.com/facebook/react/pull/7410))
- Fix issue resulting in `<input type="range">` values not updating when changing `min` or `max`. ([@troydemonbreun](https://github.com/troydemonbreun) in [#7486](https://github.com/facebook/react/pull/7486))
- Add new warning for rare case of attempting to unmount a container owned by a different copy of React. ([@ventuno](https://github.com/ventuno) in [#7456](https://github.com/facebook/react/pull/7456))
### React Test Renderer
- Fix ReactTestInstance::toJSON() with empty top-level components. ([@Morhaus](https://github.com/Morhaus) in [#7523](https://github.com/facebook/react/pull/7523))
### React Native Renderer
- Change `trackedTouchCount` invariant into a console.error for better reliability. ([@yungsters](https://github.com/yungsters) in [#7400](https://github.com/facebook/react/pull/7400))
## 15.3.0 (July 29, 2016)
### React
- Add `React.PureComponent` - a new base class to extend, replacing `react-addons-pure-render-mixin` now that mixins don't work with ES2015 classes. ([@spicyj](https://github.com/spicyj) in [#7195](https://github.com/facebook/react/pull/7195))
- Add new warning when modifying `this.props.children`. ([@jimfb](https://github.com/jimfb) in [#7001](https://github.com/facebook/react/pull/7001))
- Fixed issue with ref resolution order. ([@gaearon](https://github.com/gaearon) in [#7101](https://github.com/facebook/react/pull/7101))
- Warn when mixin is undefined. ([@swaroopsm](https://github.com/swaroopsm) in [#6158](https://github.com/facebook/react/pull/6158))
- Downgrade "unexpected batch number" invariant to a warning. ([@spicyj](https://github.com/spicyj) in [#7133](https://github.com/facebook/react/pull/7133))
- Validate arguments to `oneOf` and `oneOfType` PropTypes sooner. ([@troydemonbreun](https://github.com/troydemonbreun) in [#6316](https://github.com/facebook/react/pull/6316))
- Warn when calling PropTypes directly. ([@Aweary](https://github.com/Aweary) in [#7132](https://github.com/facebook/react/pull/7132), [#7194](https://github.com/facebook/react/pull/7194))
- Improve warning when using Maps as children. ([@keyanzhang](https://github.com/keyanzhang) in [#7260](https://github.com/facebook/react/pull/7260))
- Add additional type information to the `PropTypes.element` warning. ([@alexzherdev](https://github.com/alexzherdev) in [#7319](https://github.com/facebook/react/pull/7319))
- Improve component identification in no-op `setState` warning. ([@keyanzhang](https://github.com/keyanzhang) in [#7326](https://github.com/facebook/react/pull/7326))
### React DOM
- Fix issue with nested server rendering. ([@Aweary](https://github.com/Aweary) in [#7033](https://github.com/facebook/react/pull/7033))
- Add `xmlns`, `xmlnsXlink` to supported SVG attributes. ([@salzhrani](https://github.com/salzhrani) in [#6471](https://github.com/facebook/react/pull/6471))
- Add `referrerPolicy` to supported HTML attributes. ([@Aweary](https://github.com/Aweary) in [#7274](https://github.com/facebook/react/pull/7274))
- Fix issue resulting in `<input type="range">` initial value being rounded. ([@troydemonbreun](https://github.com/troydemonbreun) in [#7251](https://github.com/facebook/react/pull/7251))
### React Test Renderer
- Initial public release of package allowing more focused testing. Install with `npm install react-test-renderer`. ([@spicyj](https://github.com/spicyj) in [#6944](https://github.com/facebook/react/pull/6944), [#7258](https://github.com/facebook/react/pull/7258), [@iamdustan](https://github.com/iamdustan) in [#7362](https://github.com/facebook/react/pull/7362))
### React Perf Add-on
- Fix issue resulting in excessive warnings when encountering an internal measurement error. ([@sassanh](https://github.com/sassanh) in [#7299](https://github.com/facebook/react/pull/7299))
### React TestUtils Add-on
- Implement `type` property on for events created via `TestUtils.Simulate.*`. ([@yaycmyk](https://github.com/yaycmyk) in [#6154](https://github.com/facebook/react/pull/6154))
- Fix crash when running TestUtils with the production build of React. ([@gaearon](https://github.com/gaearon) in [#7246](https://github.com/facebook/react/pull/7246))
## 15.2.1 (July 8, 2016)
### React
- Fix errant warning about missing React element. ([@gaearon](https://github.com/gaearon) in [#7193](https://github.com/facebook/react/pull/7193))
- Better removal of dev-only code, leading to a small reduction in the minified production bundle size. ([@gaearon](https://github.com/gaearon) in [#7188](https://github.com/facebook/react/pull/7188), [#7189](https://github.com/facebook/react/pull/7189))
### React DOM
- Add stack trace to null input value warning. ([@jimfb](https://github.com/jimfb) in [#7040](https://github.com/facebook/react/pull/7040))
- Fix webcomponents example. ([@jalexanderfox](https://github.com/jalexanderfox) in [#7057](https://github.com/facebook/react/pull/7057))
- Fix `unstable_renderSubtreeIntoContainer` so that context properly updates when linked to state. ([@gaearon](https://github.com/gaearon) in [#7125](https://github.com/facebook/react/pull/7125))
- Improve invariant wording for void elements. ([@starkch](https://github.com/starkch) in [#7066](https://github.com/facebook/react/pull/7066))
- Ensure no errors are thrown due to event handlers in server rendering. ([@rricard](https://github.com/rricard) in [#7127](https://github.com/facebook/react/pull/7127))
- Fix regression resulting in `value`-less submit and reset inputs removing the browser-default text. ([@zpao](https://github.com/zpao) in [#7197](https://github.com/facebook/react/pull/7197))
- Fix regression resulting in empty `name` attribute being added to inputs when not provided. ([@okonet](https://github.com/okonet) in [#7199](https://github.com/facebook/react/pull/7199))
- Fix issue with nested server rendering. ([@Aweary](https://github.com/Aweary) in [#7033](https://github.com/facebook/react/pull/7033))
### React Perf Add-on
- Make `ReactPerf.start()` work properly during lifecycle methods. ([@gaearon](https://github.com/gaearon) in [#7208](https://github.com/facebook/react/pull/7208)).
### React CSSTransitionGroup Add-on
- Fix issue resulting in spurious unknown property warnings. ([@batusai513](https://github.com/batusai513) in [#7165](https://github.com/facebook/react/pull/7165))
### React Native Renderer
- Improve error handling in cross-platform touch event handling. ([@yungsters](https://github.com/yungsters) in [#7143](https://github.com/facebook/react/pull/7143))
## 15.2.0 (July 1, 2016)
### React
- Add error codes to production invariants, with links to the view the full error text. ([@keyanzhang](https://github.com/keyanzhang) in [#6948](https://github.com/facebook/react/pull/6948))
- Include component stack information in PropType validation warnings. ([@troydemonbreun](https://github.com/troydemonbreun) in [#6398](https://github.com/facebook/react/pull/6398), [@spicyj](https://github.com/spicyj) in [#6771](https://github.com/facebook/react/pull/6771))
- Include component stack information in key warnings. ([@keyanzhang](https://github.com/keyanzhang) in [#6799](https://github.com/facebook/react/pull/6799))
- Stop validating props at mount time, only validate at element creation. ([@keyanzhang](https://github.com/keyanzhang) in [#6824](https://github.com/facebook/react/pull/6824))
- New invariant providing actionable error in missing instance case. ([@yungsters](https://github.com/yungsters) in [#6990](https://github.com/facebook/react/pull/6990))
- Add `React.PropTypes.symbol` to support ES2015 Symbols as props. ([@puradox](https://github.com/puradox) in [#6377](https://github.com/facebook/react/pull/6377))
- Fix incorrect coercion of ref or key that are undefined in development ([@gaearon](https://github.com/gaearon) in [#6880](https://github.com/facebook/react/pull/6880))
- Fix a false positive when passing other element’s props to cloneElement ([@ericmatthys](https://github.com/ericmatthys) in [#6268](https://github.com/facebook/react/pull/6268))
- Warn if you attempt to define `childContextTypes` on a functional component ([@Aweary](https://github.com/Aweary) in [#6933](https://github.com/facebook/react/pull/6933))
### React DOM
- Add warning for unknown properties on DOM elements. ([@jimfb](https://github.com/jimfb) in [#6800](https://github.com/facebook/react/pull/6800), [@gm758](https://github.com/gm758) in [#7152](https://github.com/facebook/react/pull/7152))
- Properly remove attributes from custom elements. ([@grassator](https://github.com/grassator) in [#6748](https://github.com/facebook/react/pull/6748))
- Fix invalid unicode escape in attribute name regular expression. ([@nbjahan](https://github.com/nbjahan) in [#6772](https://github.com/facebook/react/pull/6772))
- Add `onLoad` handling to `<link>` element. ([@roderickhsiao](https://github.com/roderickhsiao) in [#6815](https://github.com/facebook/react/pull/6815))
- Add `onError` handling to `<source>` element. ([@wadahiro](https://github.com/wadahiro) in [#6941](https://github.com/facebook/react/pull/6941))
- Handle `value` and `defaultValue` more accurately in the DOM. ([@jimfb](https://github.com/jimfb) in [#6406](https://github.com/facebook/react/pull/6406))
- Fix events issue in environments with mutated `Object.prototype`. ([@Weizenlol](https://github.com/Weizenlol) in [#6886](https://github.com/facebook/react/pull/6886))
- Fix issue where `is="null"` ended up in the DOM in Firefox. ([@darobin](https://github.com/darobin) in [#6896](https://github.com/facebook/react/pull/6896))
- Improved performance of text escaping by using [escape-html](https://github.com/component/escape-html). ([@aickin](https://github.com/aickin) in [#6862](https://github.com/facebook/react/pull/6862))
- Fix issue with `dangerouslySetInnerHTML` and SVG in Internet Explorer. ([@joshhunt](https://github.com/joshhunt) in [#6982](https://github.com/facebook/react/pull/6982))
- Fix issue with `<textarea>` placeholders. ([@jimfb](https://github.com/jimfb) in [#7002](https://github.com/facebook/react/pull/7002))
- Fix controlled vs uncontrolled detection of `<input type="radio"/>`. ([@jimfb](https://github.com/jimfb) in [#7003](https://github.com/facebook/react/pull/7003))
- Improve performance of updating text content. ([@trueadm](https://github.com/trueadm) in [#7005](https://github.com/facebook/react/pull/7005))
- Ensure controlled `<select>` components behave the same on initial render as they do on updates. ([@yiminghe](https://github.com/yiminghe) in [#5362](https://github.com/facebook/react/pull/5362))
### React Perf Add-on
- Add `isRunning()` API. ([@nfcampos](https://github.com/nfcampos) in [#6763](https://github.com/facebook/react/pull/6763))
- Improve accuracy of lifecycle hook timing. ([@gaearon](https://github.com/gaearon) in [#6858](https://github.com/facebook/react/pull/6858))
- Fix internal errors when using ReactPerf with portal components. ([@gaearon](https://github.com/gaearon) in [#6860](https://github.com/facebook/react/pull/6860))
- Fix performance regression. ([@spicyj](https://github.com/spicyj) in [#6770](https://github.com/facebook/react/pull/6770))
- Add warning that ReactPerf is not enabled in production. ([@sashashakun](https://github.com/sashashakun) in [#6884](https://github.com/facebook/react/pull/6884))
### React CSSTransitionGroup Add-on
- Fix timing issue with `null` node. ([@keyanzhang](https://github.com/keyanzhang) in [#6958](https://github.com/facebook/react/pull/6958))
### React Native Renderer
- Dependencies on React Native modules use CommonJS requires instead of providesModule. ([@davidaurelio](https://github.com/davidaurelio) in [#6715](https://github.com/facebook/react/pull/6715))
## 15.1.0 (May 20, 2016)
### React
- Ensure we're using the latest `object-assign`, which has protection against a non-spec-compliant native `Object.assign`. ([@zpao](https://github.com/zpao) in [#6681](https://github.com/facebook/react/pull/6681))
- Add a new warning to communicate that `props` objects passed to `createElement` must be plain objects. ([@richardscarrott](https://github.com/richardscarrott) in [#6134](https://github.com/facebook/react/pull/6134))
- Fix a batching bug resulting in some lifecycle methods incorrectly being called multiple times. ([@spicyj](https://github.com/spicyj) in [#6650](https://github.com/facebook/react/pull/6650))
### React DOM
- Fix regression in custom elements support. ([@jscissr](https://github.com/jscissr) in [#6570](https://github.com/facebook/react/pull/6570))
- Stop incorrectly warning about using `onScroll` event handler with server rendering. ([@Aweary](https://github.com/Aweary) in [#6678](https://github.com/facebook/react/pull/6678))
- Fix grammar in the controlled input warning. ([@jakeboone02](https://github.com/jakeboone02) in [#6657](https://github.com/facebook/react/pull/6657))
- Fix issue preventing `<object>` nodes from being able to read `<param>` nodes in IE. ([@syranide](https://github.com/syranide) in [#6691](https://github.com/facebook/react/pull/6691))
- Fix issue resulting in crash when using experimental error boundaries with server rendering. ([@jimfb](https://github.com/jimfb) in [#6694](https://github.com/facebook/react/pull/6694))
- Add additional information to the controlled input warning. ([@borisyankov](https://github.com/borisyankov) in [#6341](https://github.com/facebook/react/pull/6341))
### React Perf Add-on
- Completely rewritten to collect data more accurately and to be easier to maintain. ([@gaearon](https://github.com/gaearon) in [#6647](https://github.com/facebook/react/pull/6647), [#6046](https://github.com/facebook/react/pull/6046))
### React Native Renderer
- Remove some special cases for platform specific branching. ([@sebmarkbage](https://github.com/sebmarkbage) in [#6660](https://github.com/facebook/react/pull/6660))
- Remove use of `merge` utility. ([@sebmarkbage](https://github.com/sebmarkbage) in [#6634](https://github.com/facebook/react/pull/6634))
- Renamed some modules to better indicate usage ([@javache](https://github.com/javache) in [#6643](https://github.com/facebook/react/pull/6643))
## 15.0.2 (April 29, 2016)
### React
- Removed extraneous files from npm package. ([@gaearon](https://github.com/gaearon) in [#6388](https://github.com/facebook/react/pull/6388))
- Ensure `componentWillUnmount` is only called once. ([@jimfb](https://github.com/jimfb) in [#6613](https://github.com/facebook/react/pull/6613))
### ReactDOM
- Fixed bug resulting in disabled buttons responding to mouse events in IE. ([@nhunzaker](https://github.com/nhunzaker) in [#6215](https://github.com/facebook/react/pull/6215))
- Ensure `<option>`s are correctly selected when inside `<optgroup>`. ([@trevorsmith](https://github.com/trevorsmith) in [#6442](https://github.com/facebook/react/pull/6442))
- Restore support for rendering into a shadow root. ([@Wildhoney](https://github.com/Wildhoney) in [#6462](https://github.com/facebook/react/pull/6462))
- Ensure nested `<body>` elements are caught when warning for invalid markup. ([@keyanzhang](https://github.com/keyanzhang) in [#6469](https://github.com/facebook/react/pull/6469))
- Improve warning when encountering multiple elements with the same key. ([@hkal](https://github.com/hkal) in [#6500](https://github.com/facebook/react/pull/6500))
### React TestUtils Add-on
- Ensure that functional components do not have an owner. ([@gaearon](https://github.com/gaearon) in [#6362](https://github.com/facebook/react/pull/6362))
- Handle invalid arguments to `scryRenderedDOMComponentsWithClass` better. ([@ipeters90](https://github.com/ipeters90) in [#6529](https://github.com/facebook/react/pull/6529))
### React Perf Add-on
- Ignore DOM operations that occur outside the batch operation. ([@gaearon](https://github.com/gaearon) in [#6516](https://github.com/facebook/react/pull/6516))
### React Native Renderer
- These files are now shipped inside the React npm package. They have no impact on React core or ReactDOM.
## 15.0.1 (April 8, 2016)
### React
- Restore `React.__spread` API to unbreak code compiled with some tools making use of this undocumented API. It is now officially deprecated. ([@zpao](https://github.com/zpao) in [#6444](https://github.com/facebook/react/pull/6444))
### ReactDOM
- Fixed issue resulting in loss of cursor position in controlled inputs. ([@spicyj](https://github.com/spicyj) in [#6449](https://github.com/facebook/react/pull/6449))
## 15.0.0 (April 7, 2016)
### Major changes
- **Initial render now uses `document.createElement` instead of generating HTML.** Previously we would generate a large string of HTML and then set `node.innerHTML`. At the time, this was decided to be faster than using `document.createElement` for the majority of cases and browsers that we supported. Browsers have continued to improve and so overwhelmingly this is no longer true. By using `createElement` we can make other parts of React faster. ([@spicyj](https://github.com/spicyj) in [#5205](https://github.com/facebook/react/pull/5205))
- **`data-reactid` is no longer on every node.** As a result of using `document.createElement`, we can prime the node cache as we create DOM nodes, allowing us to skip a potential lookup (which used the `data-reactid` attribute). Root nodes will have a `data-reactroot` attribute and server generated markup will still contain `data-reactid`. ([@spicyj](https://github.com/spicyj) in [#5205](https://github.com/facebook/react/pull/5205))
- **No more extra `<span>`s.** ReactDOM will now render plain text nodes interspersed with comment nodes that are used for demarcation. This gives us the same ability to update individual pieces of text, without creating extra nested nodes. If you were targeting these `<span>`s in your CSS, you will need to adjust accordingly. You can always render them explicitly in your components. ([@mwiencek](https://github.com/mwiencek) in [#5753](https://github.com/facebook/react/pull/5753))
- **Rendering `null` now uses comment nodes.** Previously `null` would render to `<noscript>` elements. We now use comment nodes. This may cause issues if making use of `:nth-child` CSS selectors. While we consider this rendering behavior an implementation detail of React, it's worth noting the potential problem. ([@spicyj](https://github.com/spicyj) in [#5451](https://github.com/facebook/react/pull/5451))
- **Functional components can now return `null`.** We added support for [defining stateless components as functions](/react/blog/2015/09/10/react-v0.14-rc1.html#stateless-function-components) in React 0.14. However, React 0.14 still allowed you to define a class component without extending `React.Component` or using `React.createClass()`, so [we couldn’t reliably tell if your component is a function or a class](https://github.com/facebook/react/issues/5355), and did not allow returning `null` from it. This issue is solved in React 15, and you can now return `null` from any component, whether it is a class or a function. ([@jimfb](https://github.com/jimfb) in [#5884](https://github.com/facebook/react/pull/5884))
- **Improved SVG support.** All SVG tags are now fully supported. (Uncommon SVG tags are not present on the `React.DOM` element helper, but JSX and `React.createElement` work on all tag names.) All SVG attributes that are implemented by the browsers should be supported too. If you find any attributes that we have missed, please [let us know in this issue](https://github.com/facebook/react/issues/1657). ([@zpao](https://github.com/zpao) in [#6243](https://github.com/facebook/react/pull/6243))
### Breaking changes
- **No more extra `<span>`s.**
- **`React.cloneElement()` now resolves `defaultProps`.** We fixed a bug in `React.cloneElement()` that some components may rely on. If some of the `props` received by `cloneElement()` are `undefined`, it used to return an element with `undefined` values for those props. We’re changing it to be consistent with `createElement()`. Now any `undefined` props passed to `cloneElement()` are resolved to the corresponding component’s `defaultProps`. ([@truongduy134](https://github.com/truongduy134) in [#5997](https://github.com/facebook/react/pull/5997))
- **`ReactPerf.getLastMeasurements()` is opaque.** This change won’t affect applications but may break some third-party tools. We are [revamping `ReactPerf` implementation](https://github.com/facebook/react/pull/6046) and plan to release it during the 15.x cycle. The internal performance measurement format is subject to change so, for the time being, we consider the return value of `ReactPerf.getLastMeasurements()` an opaque data structure that should not be relied upon. ([@gaearon](https://github.com/gaearon) in [#6286](https://github.com/facebook/react/pull/6286))
#### Removed deprecations
These deprecations were introduced nine months ago in v0.14 with a warning and are removed:
- Deprecated APIs are removed from the `React` top-level export: `findDOMNode`, `render`, `renderToString`, `renderToStaticMarkup`, and `unmountComponentAtNode`. As a reminder, they are now available on `ReactDOM` and `ReactDOMServer`. ([@jimfb](https://github.com/jimfb) in [#5832](https://github.com/facebook/react/pull/5832))
- Deprecated addons are removed: `batchedUpdates` and `cloneWithProps`. ([@jimfb](https://github.com/jimfb) in [#5859](https://github.com/facebook/react/pull/5859), [@zpao](https://github.com/zpao) in [#6016](https://github.com/facebook/react/pull/6016))
- Deprecated component instance methods are removed: `setProps`, `replaceProps`, and `getDOMNode`. ([@jimfb](https://github.com/jimfb) in [#5570](https://github.com/facebook/react/pull/5570))
- Deprecated CommonJS `react/addons` entry point is removed. As a reminder, you should use separate `react-addons-*` packages instead. This only applies if you use the CommonJS builds. ([@gaearon](https://github.com/gaearon) in [#6285](https://github.com/facebook/react/pull/6285))
- Passing `children` to void elements like `<input>` was deprecated, and now throws an error. ([@jonhester](https://github.com/jonhester) in [#3372](https://github.com/facebook/react/pull/3372))
- React-specific properties on DOM `refs` (e.g. `this.refs.div.props`) were deprecated, and are removed now. ([@jimfb](https://github.com/jimfb) in [#5495](https://github.com/facebook/react/pull/5495))
### New deprecations, introduced with a warning
Each of these changes will continue to work as before with a new warning until the release of React 16 so you can upgrade your code gradually.
-`LinkedStateMixin` and `valueLink` are now deprecated due to very low popularity. If you need this, you can use a wrapper component that implements the same behavior: [react-linked-input](https://www.npmjs.com/package/react-linked-input). ([@jimfb](https://github.com/jimfb) in [#6127](https://github.com/facebook/react/pull/6127))
- Future versions of React will treat `<input value={null}>` as a request to clear the input. However, React 0.14 has been ignoring `value={null}`. React 15 warns you on a `null` input value and offers you to clarify your intention. To fix the warning, you may explicitly pass an empty string to clear a controlled input, or pass `undefined` to make the input uncontrolled. ([@antoaravinth](https://github.com/antoaravinth) in [#5048](https://github.com/facebook/react/pull/5048))
-`ReactPerf.printDOM()` was renamed to `ReactPerf.printOperations()`, and `ReactPerf.getMeasurementsSummaryMap()` was renamed to `ReactPerf.getWasted()`. ([@gaearon](https://github.com/gaearon) in [#6287](https://github.com/facebook/react/pull/6287))
### New helpful warnings
- If you use a minified copy of the _development_ build, React DOM kindly encourages you to use the faster production build instead. ([@spicyj](https://github.com/spicyj) in [#5083](https://github.com/facebook/react/pull/5083))
- React DOM: When specifying a unit-less CSS value as a string, a future version will not add `px` automatically. This version now warns in this case (ex: writing `style={{'{{'}}width: '300'}}`. Unitless *number* values like `width: 300` are unchanged. ([@pluma](https://github.com/pluma) in [#5140](https://github.com/facebook/react/pull/5140))
- Synthetic Events will now warn when setting and accessing properties (which will not get cleared appropriately), as well as warn on access after an event has been returned to the pool. ([@kentcdodds](https://github.com/kentcdodds) in [#5940](https://github.com/facebook/react/pull/5940) and [@koba04](https://github.com/koba04) in [#5947](https://github.com/facebook/react/pull/5947))
- Elements will now warn when attempting to read `ref` and `key` from the props. ([@prometheansacrifice](https://github.com/prometheansacrifice) in [#5744](https://github.com/facebook/react/pull/5744))
- React will now warn if you pass a different `props` object to `super()` in the constructor. ([@prometheansacrifice](https://github.com/prometheansacrifice) in [#5346](https://github.com/facebook/react/pull/5346))
- React will now warn if you call `setState()` inside `getChildContext()`. ([@raineroviir](https://github.com/raineroviir) in [#6121](https://github.com/facebook/react/pull/6121))
- React DOM now attempts to warn for mistyped event handlers on DOM elements, such as `onclick` which should be `onClick`. ([@ali](https://github.com/ali) in [#5361](https://github.com/facebook/react/pull/5361))
- React DOM now warns about `NaN` values in `style`. ([@jontewks](https://github.com/jontewks) in [#5811](https://github.com/facebook/react/pull/5811))
- React DOM now warns if you specify both `value` and `defaultValue` for an input. ([@mgmcdermott](https://github.com/mgmcdermott) in [#5823](https://github.com/facebook/react/pull/5823))
- React DOM now warns if an input switches between being controlled and uncontrolled. ([@TheBlasfem](https://github.com/TheBlasfem) in [#5864](https://github.com/facebook/react/pull/5864))
- React DOM now warns if you specify `onFocusIn` or `onFocusOut` handlers as they are unnecessary in React. ([@jontewks](https://github.com/jontewks) in [#6296](https://github.com/facebook/react/pull/6296))
- React now prints a descriptive error message when you pass an invalid callback as the last argument to `ReactDOM.render()`, `this.setState()`, or `this.forceUpdate()`. ([@conorhastings](https://github.com/conorhastings) in [#5193](https://github.com/facebook/react/pull/5193) and [@gaearon](https://github.com/gaearon) in [#6310](https://github.com/facebook/react/pull/6310))
- Add-Ons: `TestUtils.Simulate()` now prints a helpful message if you attempt to use it with shallow rendering. ([@conorhastings](https://github.com/conorhastings) in [#5358](https://github.com/facebook/react/pull/5358))
- PropTypes: `arrayOf()` and `objectOf()` provide better error messages for invalid arguments. ([@chicoxyzzy](https://github.com/chicoxyzzy) in [#5390](https://github.com/facebook/react/pull/5390))
### Notable bug fixes
- Fixed multiple small memory leaks. ([@spicyj](https://github.com/spicyj) in [#4983](https://github.com/facebook/react/pull/4983) and [@victor-homyakov](https://github.com/victor-homyakov) in [#6309](https://github.com/facebook/react/pull/6309))
- Input events are handled more reliably in IE 10 and IE 11; spurious events no longer fire when using a placeholder. ([@jquense](https://github.com/jquense) in [#4051](https://github.com/facebook/react/pull/4051))
- The `componentWillReceiveProps()` lifecycle method is now consistently called when `context` changes. ([@milesj](https://github.com/milesj) in [#5787](https://github.com/facebook/react/pull/5787))
-`React.cloneElement()` doesn’t append slash to an existing `key` when used inside `React.Children.map()`. ([@ianobermiller](https://github.com/ianobermiller) in [#5892](https://github.com/facebook/react/pull/5892))
- React DOM now supports the `cite` and `profile` HTML attributes. ([@AprilArcus](https://github.com/AprilArcus) in [#6094](https://github.com/facebook/react/pull/6094) and [@saiichihashimoto](https://github.com/saiichihashimoto) in [#6032](https://github.com/facebook/react/pull/6032))
- React DOM now supports `cssFloat`, `gridRow` and `gridColumn` CSS properties. ([@stevenvachon](https://github.com/stevenvachon) in [#6133](https://github.com/facebook/react/pull/6133) and [@mnordick](https://github.com/mnordick) in [#4779](https://github.com/facebook/react/pull/4779))
- React DOM now correctly handles `borderImageOutset`, `borderImageWidth`, `borderImageSlice`, `floodOpacity`, `strokeDasharray`, and `strokeMiterlimit` as unitless CSS properties. ([@rofrischmann](https://github.com/rofrischmann) in [#6210](https://github.com/facebook/react/pull/6210) and [#6270](https://github.com/facebook/react/pull/6270))
- React DOM now supports the `onAnimationStart`, `onAnimationEnd`, `onAnimationIteration`, `onTransitionEnd`, and `onInvalid` events. Support for `onLoad` has been added to `object` elements. ([@tomduncalf](https://github.com/tomduncalf) in [#5187](https://github.com/facebook/react/pull/5187), [@milesj](https://github.com/milesj) in [#6005](https://github.com/facebook/react/pull/6005), and [@ara4n](https://github.com/ara4n) in [#5781](https://github.com/facebook/react/pull/5781))
- React DOM now defaults to using DOM attributes instead of properties, which fixes a few edge case bugs. Additionally the nullification of values (ex: `href={null}`) now results in the forceful removal, no longer trying to set to the default value used by browsers in the absence of a value. ([@syranide](https://github.com/syranide) in [#1510](https://github.com/facebook/react/pull/1510))
- React DOM does not mistakingly coerce `children` to strings for Web Components. ([@jimfb](https://github.com/jimfb) in [#5093](https://github.com/facebook/react/pull/5093))
- React DOM now correctly normalizes SVG `<use>` events. ([@edmellum](https://github.com/edmellum) in [#5720](https://github.com/facebook/react/pull/5720))
- React DOM does not throw if a `<select>` is unmounted while its `onChange` handler is executing. ([@sambev](https://github.com/sambev) in [#6028](https://github.com/facebook/react/pull/6028))
- React DOM does not throw in Windows 8 apps. ([@Andrew8xx8](https://github.com/Andrew8xx8) in [#6063](https://github.com/facebook/react/pull/6063))
- React DOM does not throw when asynchronously unmounting a child with a `ref`. ([@yiminghe](https://github.com/yiminghe) in [#6095](https://github.com/facebook/react/pull/6095))
- React DOM no longer forces synchronous layout because of scroll position tracking. ([@syranide](https://github.com/syranide) in [#2271](https://github.com/facebook/react/pull/2271))
-`Object.is` is used in a number of places to compare values, which leads to fewer false positives, especially involving `NaN`. In particular, this affects the `shallowCompare` add-on. ([@chicoxyzzy](https://github.com/chicoxyzzy) in [#6132](https://github.com/facebook/react/pull/6132))
- Add-Ons: ReactPerf no longer instruments adding or removing an event listener because they don’t really touch the DOM due to event delegation. ([@antoaravinth](https://github.com/antoaravinth) in [#5209](https://github.com/facebook/react/pull/5209))
###Other improvements
- React now uses `loose-envify` instead of `envify` so it installs fewer transitive dependencies. ([@qerub](https://github.com/qerub) in [#6303](https://github.com/facebook/react/pull/6303))
- Shallow renderer now exposes `getMountedInstance()`. ([@glenjamin](https://github.com/glenjamin) in [#4918](https://github.com/facebook/react/pull/4918))
- Shallow renderer now returns the rendered output from `render()`. ([@simonewebdesign](https://github.com/simonewebdesign) in [#5411](https://github.com/facebook/react/pull/5411))
- React no longer depends on ES5 *shams* for `Object.create` and `Object.freeze` in older environments. It still, however, requires ES5 *shims* in those environments. ([@dgreensp](https://github.com/dgreensp) in [#4959](https://github.com/facebook/react/pull/4959))
- React DOM now allows `data-` attributes with names that start with numbers. ([@nLight](https://github.com/nLight) in [#5216](https://github.com/facebook/react/pull/5216))
- React DOM adds a new `suppressContentEditableWarning` prop for components like [Draft.js](https://facebook.github.io/draft-js/) that intentionally manage `contentEditable` children with React. ([@mxstbr](https://github.com/mxstbr) in [#6112](https://github.com/facebook/react/pull/6112))
- React improves the performance for `createClass()` on complex specs. ([@spicyj](https://github.com/spicyj) in [#5550](https://github.com/facebook/react/pull/5550))
## 0.14.8 (March 29, 2016)
### React
@@ -88,7 +435,7 @@
### Major changes
- Split the main `react` package into two: `react` and `react-dom`. This paves the way to writing components that can be shared between the web version of React and React Native. This means you will need to include both files and some functions have been moved from `React` to `ReactDOM`.
- Addons have been moved to seperate packages (`react-addons-clone-with-props`, `react-addons-create-fragment`, `react-addons-css-transition-group`, `react-addons-linked-state-mixin`, `react-addons-perf`, `react-addons-pure-render-mixin`, `react-addons-shallow-compare`, `react-addons-test-utils`, `react-addons-transition-group`, `react-addons-update`, `ReactDOM.unstable_batchedUpdates`).
- Addons have been moved to separate packages (`react-addons-clone-with-props`, `react-addons-create-fragment`, `react-addons-css-transition-group`, `react-addons-linked-state-mixin`, `react-addons-perf`, `react-addons-pure-render-mixin`, `react-addons-shallow-compare`, `react-addons-test-utils`, `react-addons-transition-group`, `react-addons-update`, `ReactDOM.unstable_batchedUpdates`).
- Stateless functional components - React components were previously created using React.createClass or using ES6 classes. This release adds a [new syntax](https://facebook.github.io/react/docs/reusable-components.html#stateless-functions) where a user defines a single [stateless render function](https://facebook.github.io/react/docs/reusable-components.html#stateless-functions) (with one parameter: `props`) which returns a JSX element, and this function may be used as a component.
- Refs to DOM components as the DOM node itself. Previously the only useful thing you can do with a DOM component is call `getDOMNode()` to get the underlying DOM node. Starting with this release, a ref to a DOM component _is_ the actual DOM node. **Note that refs to custom (user-defined) components work exactly as before; only the built-in DOM components are affected by this change.**
@@ -97,7 +444,7 @@
-`React.initializeTouchEvents` is no longer necessary and has been removed completely. Touch events now work automatically.
- Add-Ons: Due to the DOM node refs change mentioned above, `TestUtils.findAllInRenderedTree` and related helpers are no longer able to take a DOM component, only a custom component.
- The `props` object is now frozen, so mutating props after creating a component element is no longer supported. In most cases, [`React.cloneElement`](https://facebook.github.io/react/docs/top-level-api.html#react.cloneelement) should be used instead. This change makes your components easier to reason about and enables the compiler optimizations mentioned above.
- The `props` object is now frozen, so mutating props after creating a component element is no longer supported. In most cases, [`React.cloneElement`](https://facebook.github.io/react/docs/react-api.html#cloneelement) should be used instead. This change makes your components easier to reason about and enables the compiler optimizations mentioned above.
- Plain objects are no longer supported as React children; arrays should be used instead. You can use the [`createFragment`](https://facebook.github.io/react/docs/create-fragment.html) helper to migrate, which now returns an array.
- Add-Ons: `classSet` has been removed. Use [classnames](https://github.com/JedWatson/classnames) instead.
- Web components (custom elements) now use native property names. Eg: `class` instead of `className`.
@@ -108,7 +455,7 @@
-`setProps` and `replaceProps` are now deprecated. Instead, call ReactDOM.render again at the top level with the new props.
- ES6 component classes must now extend `React.Component` in order to enable stateless function components. The [ES3 module pattern](https://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#other-languages) will continue to work.
- Reusing and mutating a `style` object between renders has been deprecated. This mirrors our change to freeze the `props` object.
- Add-Ons: `cloneWithProps` is now deprecated. Use [`React.cloneElement`](https://facebook.github.io/react/docs/top-level-api.html#react.cloneelement) instead (unlike `cloneWithProps`, `cloneElement` does not merge `className` or `style` automatically; you can merge them manually if needed).
- Add-Ons: `cloneWithProps` is now deprecated. Use [`React.cloneElement`](https://facebook.github.io/react/docs/react-api.html#cloneelement) instead (unlike `cloneWithProps`, `cloneElement` does not merge `className` or `style` automatically; you can merge them manually if needed).
- Add-Ons: To improve reliability, `CSSTransitionGroup` will no longer listen to transition events. Instead, you should specify transition durations manually using props such as `transitionEnterTimeout={500}`.
### Notable enhancements
@@ -202,7 +549,7 @@
#### Bug Fixes
* Immutabilty Helpers: Ensure it supports `hasOwnProperty` as an object key
* Immutability Helpers: Ensure it supports `hasOwnProperty` as an object key
### React Tools
@@ -733,14 +1080,14 @@
* Upgrade Commoner so `require` statements are no longer relativized when passing through the transformer. This was a feature needed when building React, but doesn't translate well for other consumers of `bin/jsx`.
* Upgraded our dependencies on Commoner and Recast so they use a different directory for their cache.
* Freeze our esprima dependency.
* Freeze our Esprima dependency.
## 0.3.2 (May 31, 2013)
### JSX
* Improved compatability with other coding styles (specifically, multiple assignments with a single `var`).
* Improved compatibility with other coding styles (specifically, multiple assignments with a single `var`).
React is one of Facebook's first open source projects that is both under very active development and is also being used to ship code to everybody on [facebook.com](https://www.facebook.com). We're still working out the kinks to make contributing to this project as easy and transparent as possible, but we're not quite there yet. Hopefully this document makes the process for contributing clear and answers some questions that you may have.
Want to contribute to React? There are a few things you need to know.
## [Code of Conduct](https://code.facebook.com/codeofconduct)
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read [the full text](https://code.facebook.com/codeofconduct) so that you can understand what actions will and will not be tolerated.
## Our Development Process
Some of the core team will be working directly on GitHub. These changes will be public from the beginning. Other changesets will come via a bridge with Facebook's internal source control. This is a necessity as it allows engineers at Facebook outside of the core team to move fast and contribute from an environment they are comfortable in.
### `master` is unsafe
We will do our best to keep `master` in good shape, with tests passing at all times. But in order to move fast, we will make API changes that your application might not be compatible with. We will do our best to communicate these changes and always version appropriately so you can lock into a specific version if need be.
### Test Suite
Use `grunt test` to run the full test suite with PhantomJS.
This command is just a facade to [Jest](https://facebook.github.io/jest/). You may optionally run `npm install -g jest-cli` and use Jest commands directly to have more control over how tests are executed.
For example, `jest --watch` lets you automatically run the test suite on every file change.
You can also run a subset of tests by passing a prefix to `jest`. For instance, `jest ReactDOMSVG` will only run tests in the files that start with `ReactDOMSVG`, such as `ReactDOMSVG-test.js`.
When you know which tests you want to run, you can achieve a fast feedback loop by using these two features together. For example, `jest ReactDOMSVG --watch` will re-run only the matching tests on every change.
Just make sure to run the whole test suite before submitting a pull request!
### Pull Requests
**Working on your first Pull Request?** You can learn how from this *free* series [How to Contribute to an Open Source Project on GitHub](https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github)
The core team will be monitoring for pull requests. When we get one, we'll run some Facebook-specific integration tests on it first. From here, we'll need to get another person to sign off on the changes and then merge the pull request. For API changes we may need to fix internal uses, which could cause some delay. We'll do our best to provide updates and feedback throughout the process.
*Before* submitting a pull request, please make sure the following is done…
1. Fork the repo and create your branch from `master`.
2. If you've added code that should be tested, add tests!
3. If you've changed APIs, update the documentation.
4. Ensure the test suite passes (`grunt test`).
5. Make sure your code lints (`grunt lint`) - we've done our best to make sure these rules match our internal linting guidelines.
6. If you haven't already, complete the CLA.
### Contributor License Agreement (CLA)
In order to accept your pull request, we need you to submit a CLA. You only need to do this once, so if you've done this for another Facebook open source project, you're good to go. If you are submitting a pull request for the first time, just let us know that you have completed the CLA and we can cross-check with your GitHub username.
[Complete your CLA here.](https://code.facebook.com/cla)
## Bugs
### Where to Find Known Issues
We will be using GitHub Issues for our public bugs. We will keep a close eye on this and try to make it clear when we have an internal fix in progress. Before filing a new task, try to make sure your problem doesn't already exist.
### Reporting New Issues
The best way to get your bug fixed is to provide a reduced test case. jsFiddle, jsBin, and other sites provide a way to give live examples. Those are especially helpful though may not work for `JSX`-based code.
### Security Bugs
Facebook has a [bounty program](https://www.facebook.com/whitehat/) for the safe disclosure of security bugs. With that in mind, please do not file public issues; go through the process outlined on that page.
## How to Get in Touch
* IRC - [#reactjs on freenode](https://webchat.freenode.net/?channels=reactjs)
* Discussion forum - [discuss.reactjs.org](https://discuss.reactjs.org/)
## Meeting Notes
React team meets once a week to discuss the development of React, future plans, and priorities.
You can find the meeting notes in a [dedicated repository](https://github.com/reactjs/core-notes/).
## Style Guide
Our linter will catch most styling issues that may exist in your code.
You can check the status of your code styling by simply running: `grunt lint`
However, there are still some styles that the linter cannot pick up. If you are unsure about something, looking at [Airbnb's Style Guide](https://github.com/airbnb/javascript) will guide you in the right direction.
### Code Conventions
* Use semicolons `;`
* Commas last `,`
* 2 spaces for indentation (no tabs)
* Prefer `'` over `"`
*`'use strict';`
* 80 character line length
* Write "attractive" code
* Do not use the optional parameters of `setTimeout` and `setInterval`
### Documentation
* Do not wrap lines at 80 characters
## License
By contributing to React, you agree that your contributions will be licensed under its BSD license.
We wrote a **[contribution guide](https://facebook.github.io/react/contributing/how-to-contribute.html)** to help you get started.
React is a JavaScript library for building user interfaces.
* **Just the UI:** Lots of people use React as the V in MVC. Since React makes no assumptions about the rest of your technology stack, it's easy to try it out on a small feature in an existing project.
* **Virtual DOM:** React abstracts away the DOM from you, giving a simpler programming model and better performance. React can also render on the server using Node, and it can power native apps using [React Native](https://facebook.github.io/react-native/).
* **Data flow:** React implements one-way reactive data flow which reduces boilerplate and is easier to reason about than traditional data binding.
**NEW**! Check out our newest project [React Native](https://github.com/facebook/react-native), which uses React and JavaScript to create native mobile apps.
* **Declarative:** React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable, simpler to understand, and easier to debug.
* **Component-Based:** Build encapsulated components that manage their own state, then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep state out of the DOM.
* **Learn Once, Write Anywhere:** We don't make assumptions about the rest of your technology stack, so you can develop new features in React without rewriting existing code. React can also render on the server using Node and power mobile apps using [React Native](https://facebook.github.io/react-native/).
[Learn how to use React in your own project](https://facebook.github.io/react/docs/getting-started.html).
@@ -14,12 +12,12 @@ React is a JavaScript library for building user interfaces.
We have several examples [on the website](https://facebook.github.io/react/). Here is the first one to get you started:
```js
varHelloMessage=React.createClass({
render:function(){
```jsx
classHelloMessageextendsReact.Component{
render(){
return<div>Hello{this.props.name}</div>;
}
});
}
ReactDOM.render(
<HelloMessagename="John"/>,
@@ -29,76 +27,35 @@ ReactDOM.render(
This example will render "Hello John" into a container on the page.
You'll notice that we used an HTML-like syntax; [we call it JSX](https://facebook.github.io/react/docs/jsx-in-depth.html). JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML. A simple transform is included with React that allows converting JSX into native JavaScript for browsers to digest.
You'll notice that we used an HTML-like syntax; [we call it JSX](https://facebook.github.io/react/docs/introducing-jsx.html). JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML. We recommend using [Babel](https://babeljs.io/) with a [React preset](https://babeljs.io/docs/plugins/preset-react/) to convert JSX into native JavaScript for browsers to digest.
## Installation
The fastest way to get started is to serve JavaScript from the CDN (also available on [cdnjs](https://cdnjs.com/libraries/react) and [jsdelivr](https://www.jsdelivr.com/projects/react)):
React is available as the `react` package on [npm](https://www.npmjs.com/). It is also available on a [CDN](https://facebook.github.io/react/docs/installation.html#using-a-cdn).
React is flexible and can be used in a variety of projects. You can create new apps with it, but you can also gradually introduce it into an existing codebase without doing a rewrite.
We've also built a [starter kit](https://facebook.github.io/react/downloads/react-0.14.8.zip) which might be useful if this is your first time using React. It includes a webpage with an example of using React with live code.
The recommended way to install React depends on your project. Here you can find short guides for the most common scenarios:
If you'd like to use [bower](http://bower.io), it's as easy as:
* [Trying Out React](https://facebook.github.io/react/docs/installation.html#trying-out-react)
* [Creating a Single Page Application](https://facebook.github.io/react/docs/installation.html#creating-a-single-page-application)
* [Adding React to an Existing Application](https://facebook.github.io/react/docs/installation.html#adding-react-to-an-existing-application)
```sh
bower install --save react
```
## Contributing
And it's just as easy with [npm](http://npmjs.com):
The main purpose of this repository is to continue to evolve React core, making it faster and easier to use. Development of React happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React.
```sh
npm i --save react
```
### [Code of Conduct](https://code.facebook.com/codeofconduct)
## Contribute
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read [the full text](https://code.facebook.com/codeofconduct) so that you can understand what actions will and will not be tolerated.
The main purpose of this repository is to continue to evolve React core, making it faster and easier to use. If you're interested in helping with that, then keep reading. If you're not interested in helping right now that's ok too. :) Any feedback you have about using React would be greatly appreciated.
### Contributing Guide
### Building Your Copy of React
The process to build `react.js` is built entirely on top of node.js, using many libraries you may already be familiar with.
#### Prerequisites
* You have `node` installed at v4.0.0+ and `npm` at v2.0.0+.
* You are familiar with `npm` and know whether or not you need to use `sudo` when installing packages globally.
* You are familiar with `git`.
#### Build
Once you have the repository cloned, building a copy of `react.js` is really easy.
```sh
# grunt-cli is needed by grunt; you might have this installed already
npm install -g grunt-cli
npm install
grunt build
```
At this point, you should now have a `build/` directory populated with everything you need to use React. The examples should all work.
### Grunt
We use grunt to automate many tasks. Run `grunt -h` to see a mostly complete listing. The important ones to know:
```sh
# Build and run tests with PhantomJS
grunt test
# Lint the code with ESLint
grunt lint
# Wipe out build directory
grunt clean
```
Read our [contributing guide](https://facebook.github.io/react/contributing/how-to-contribute.html) to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React.
### Good First Bug
To help you get your feet wet and get you familiar with our contribution process, we have a list of [good first bugs](https://github.com/facebook/react/labels/good%20first%20bug) that contain bugs which are fairly easy to fix. This is a great place to get started.
To help you get your feet wet and get you familiar with our contribution process, we have a list of [good first bugs](https://github.com/facebook/react/labels/good%20first%20bug) that contain bugs which are fairly easy to fix. This is a great place to get started.
### License
@@ -108,9 +65,5 @@ React documentation is [Creative Commons licensed](./LICENSE-docs).
Examples provided in this repository and in the documentation are [separately licensed](./LICENSE-examples).
### More…
There's only so much we can cram in here. To read more about the community and guidelines for submitting pull requests, please read the [Contributing document](CONTRIBUTING.md).
## Troubleshooting
See the [Troubleshooting Guide](https://github.com/facebook/react/wiki/Troubleshooting)
@@ -8,14 +8,17 @@ If you are working on the site, you will want to install and run a local copy of
### Dependencies
In order to use Jekyll, you will need to have Ruby installed.
In order to use Jekyll, you will need to have Ruby installed. macOS comes pre-installed with Ruby, but you may need to update RubyGems (via `gem update --system`).
Otherwise, [RVM](https://rvm.io/) and [rbenv](https://github.com/sstephenson/rbenv) are popular ways to install Ruby.
MacOS X comes pre-installed with Ruby, but you may need to update RubyGems (via `gem update --system`).
Otherwise, [RVM](https://rvm.io/) and [rbenv](https://github.com/sstephenson/rbenv) are popular ways to install Ruby.
The version of the Pygment syntax highlighter used by Jekyll requires Python 2.7.x (not 3.x). macOS comes pre-installed with Python 2.7, but you may need to install it on other OSs.
[Domenic Denicola](http://domenicdenicola.com/) wrote a slide deck about the great applications of ES6 features and one slide shows how we could use Template Strings to compile JSX at run-time without the need for a pre-processing phase.
[Tom Occhino](http://tomocchino.com/) and [Jordan Walke](https://github.com/jordwalke), React developers, did a presentation of React at Facebook Seattle's office. Check out the first 25 minutes for the presentation and the remaining 45 for a Q&A. I highly recommend you watching this video.
@@ -29,7 +29,7 @@ We organized a React hackathon last week-end in the Facebook Seattle office. 50
The video will be available soon on the [JSConf EU website](http://2013.jsconf.eu/speakers/pete-hunt-react-rethinking-best-practices.html), but in the meantime, here are Pete's slides:
> You see that React components are defined using a regular JS object. Some properties and methods of the object such as render() have special meanings, the rest is upforgrabs.
>
> [Read the full article...](http://www.phpied.com/reactive-table/)
@@ -9,7 +9,7 @@ This round-up is the proof that React has taken off from its Facebook's root: it
[Steve Luscher](https://github.com/steveluscher) working at [LeanPub](https://leanpub.com/) made a 30 min talk at [Super VanJS](https://twitter.com/vanjs). He does a remarkable job at explaining why React is so fast with very exciting demos using the HTML5 Audio API.
@@ -10,7 +10,7 @@ Happy holidays! This blog post is a little-late Christmas present for all the Re
[Pete Hunt](http://www.petehunt.net/) wrote three demos showing that React can be used to run 60fps native-like experiences on mobile web. A frosted glass effect, an image gallery with 3d animations and an infinite scroll view.
[Try out the demos!](https://petehunt.github.io/react-touch/)
@@ -19,7 +19,7 @@ Happy holidays! This blog post is a little-late Christmas present for all the Re
[Stoyan Stefanov](http://www.phpied.com/) talked at Joe Dev On Tech about React. He goes over all the features of the library and ends with a concrete example.
@@ -115,4 +115,3 @@ var MyComponent = React.createClass({
## Random Tweet
<center><blockquote class="twitter-tweet" lang="en"><p>I may be starting to get annoying with this, but ReactJS is really exciting. I truly feel the virtual DOM is a game changer.</p>— Eric Florenzano (@ericflo) <a href="https://twitter.com/ericflo/statuses/413842834974732288">December 20, 2013</a></blockquote></center>
With the new year, we thought you'd enjoy some new tools for debugging React code. Today we're releasing the [React Developer Tools](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi), an extension to the Chrome Developer Tools. [Download them from the Chrome Web Store](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi).
You will get a new tab titled "React" in your Chrome DevTools. This tab shows you a list of the root React Components that are rendered on the page as well as the subcomponents that each root renders.
@@ -15,4 +15,3 @@ When you inspect a DOM element using the regular Elements tab, you can switch ov
We hope these tools will help your team better understand your component hierarchy and track down bugs. We're very excited about this initial launch and appreciate any feedback you may have. As always, we also accept [pull requests on GitHub](https://github.com/facebook/react-devtools).
@@ -28,7 +28,7 @@ React is only one-piece of your web application stack. [Mark Lussier](https://gi
## React Rails Tutorial
[Selem Delul](http://selem.im) bundled the [React Tutorial](/react/docs/tutorial.html) into a rails app. This is a good example on how to get started with a rails project.
[Selem Delul](http://selem.im) bundled the [React Tutorial](/react/tutorial/tutorial.html) into a rails app. This is a good example on how to get started with a rails project.
@@ -9,7 +9,7 @@ There have been many posts recently covering the <i>why</i> and <i>how</i> of Re
## React in a nutshell
Got five minutes to pitch React to your coworkers? John Lynch ([@johnrlynch](https://twitter.com/johnrlynch)) put together [this excellent and refreshing slideshow](http://slid.es/johnlynch/reactjs):
To summarize, Flux works well for us because the single directional data flow makes it easy to understand and modify an application as it becomes more complicated. We found that two-way data bindings lead to cascading updates, where changing one data model led to another data model updating, making it very difficult to predict what would change as the result of a single user interaction.
@@ -23,7 +23,7 @@ These are some of the links that often pop up on the #reactjs IRC channel. If yo
The core concepts React themselves is something very valuable that the community is exploring and pushing further. A year ago, we wouldn't have imagined something like [Bruce Hauman](http://rigsomelight.com)'s [Flappy Bird ClojureScript port](http://rigsomelight.com/2014/05/01/interactive-programming-flappy-bird-clojurescript.html), whose interactive programming has been made possible through React:
And don't forget [Pete Hunt](https://github.com/petehunt)'s Wolfenstein 3D rendering engine in React ([source code](https://github.com/petehunt/wolfenstein3D-react/blob/master/js/renderer.js#L183)). While it's nearly a year old, it's still a nice demo.
@@ -16,14 +16,14 @@ It's an exciting time for React as there are now more commits from open source c
At the last [JSConf.us](http://2014.jsconf.us/), Vjeux talked about the design decisions made in the API that allows it to scale to a large number of developers. If you don't have 20 minutes, take a look at the [annotated slides](https://speakerdeck.com/vjeux/why-does-react-scale-jsconf-2014).
One of the best features of React is that it provides the foundations to implement concepts that were otherwise extremely difficult, like server-side rendering, undo-redo, rendering to non-DOM environments like canvas... [Dan Abramov](https://twitter.com/dan_abramov) got hot code reloading working with webpack in order to [live edit a React project](https://gaearon.github.io/react-hot-loader/)!
In related news, the next [React SF Meetup](http://www.meetup.com/ReactJS-San-Francisco/events/195518392/) will be from Prezi: [“Immediate Mode on the Web: How We Implemented the Prezi Viewer in JavaScript”](https://medium.com/prezi-engineering/how-and-why-prezi-turned-to-javascript-56e0ca57d135). While not in React, their tech is really awesome and shares a lot of React's design principles and perf optimizations.
@@ -20,7 +20,7 @@ This has been an exciting summer as four big companies: Yahoo, Mozilla, Airbnb a
[Vjeux](http://blog.vjeux.com/), from the React team, gave a talk at OSCON on the history of React and the various optimizations strategies that are implemented. You can also check out the [annotated slides](https://speakerdeck.com/vjeux/oscon-react-architecture) or [Chris Dawson](http://thenewstack.io/author/chrisdawson/)'s notes titled [JavaScript’s History and How it Led To React](http://thenewstack.io/javascripts-history-and-how-it-led-to-reactjs/).
@@ -10,7 +10,7 @@ This round-up is a special edition on [Flux](https://facebook.github.io/flux/).
Facebook engineers [Jing Chen](https://github.com/jingc) and [Bill Fisher](https://github.com/fisherwebdev) gave a talk about Flux and React at [ForwardJS](http://forwardjs.com/), and how using an application architecture with a unidirectional data flow helped solve recurring bugs.
Last but not least, Flux and React ideas are not limited to JavaScript inside of the browser. The iOS team at Facebook re-implemented Newsfeed using very similar patterns.
@@ -14,11 +14,11 @@ Murilo Pereira ([mpereira](https://github.com/mpereira)) tussles with the topic
I ([steveluscher](https://github.com/steveluscher)) spoke at Manning Publications' “Powered By JavaScript” Strangeloop pre-conf in St. Louis. There, I proposed a new notation to talk about development complexity – Big-Coffee Notation ☕(n) – and spoke about the features of React that help keep our Big-Coffee from going quadratic, as our user interfaces get more complex.
James Pearce ([jamesgpearce](https://github.com/jamesgpearce)) carried Big-Coffee all the way to Raleigh, NC. At the _All Things Open_ conference, he spoke about some of the design decisions that went into React, particularly those that lend themselves to simpler, more reliable code.
@@ -38,7 +38,7 @@ Ryan Florence ([rpflorence](https://github.com/rpflorence])) and Michael Jackson
Jonathan Beebe ([somethingkindawierd](https://github.com/somethingkindawierd)) spoke about how he uses React to build tools that deliver hope to those trying to make the best of a bad situation. Watch his talk from this year's _Nodevember_ conference in Nashville
If you take a peek under the covers, you'll find that React powers [Carousel](https://blog.carousel.com/2014/11/introducing-carousel-for-web-ipad-and-android-tablet/), Dropbox's new photo and video gallery app.
@@ -48,7 +48,7 @@ We enjoyed a cinematic/narrative experience with this React-powered, interactive
Spend the next 60 seconds watching Daniel Woelfel ([dwwoelfel](https://github.com/dwwoelfel)) serialize a React app's state as a string, then deserialize it to produce a working UI. Read about how he uses this technique to [reproduce bugs](http://blog.circleci.com/local-state-global-concerns/) reported to him by his users.
@@ -245,7 +245,7 @@ It was a privilege to welcome the React community to Facebook HQ on January 28
The conference is over, but the conversation has just begun.
**Mihai Parparita** detailed his efforts to [hack his way to a React.js Conf ticket](http://blog.persistent.info/2014/12/html-munging-my-way-to-reactjs-conf.html); **James Long** blogged about [his first encounter with React Native](http://jlongster.com/First-Impressions-using-React-Native); **Eric Florenzano** talked about how he perceives the [impact of Relay, GraphQL, and React Native](https://medium.com/@ericflo/facebook-just-taught-us-all-how-to-build-websites-51f1e7e996f2) on software development; **Margaret Staples** blogged about her experience of [being on-campus at Facebook HQ](http://deadlugosi.blogspot.com/2015/02/facebook-gave-me-ice-cream.html); **Jeff Barczewski** tied his experience of attending the conference up with a bow in this [blog post filled with photos, videos, and links](http://codewinds.com/blog/2015-02-04-reactjs-conf.html); **Kevin Old** left us with [his takeaways](http://kevinold.com/2015/01/31/takeaways-from-reactjs-conf-2015.html); **Paul Wittmann** found React Native [freshly on his radar](http://www.railslove.com/stories/fresh-on-our-radar-react-native); and finally, undeterred by not being able to attend the conference in person, **Justin Ball** [summarized it from afar](http://www.justinball.com/2015/02/03/i-didn't-attend-react.js-conf/).
**Mihai Parparita** detailed his efforts to [hack his way to a React.js Conf ticket](http://blog.persistent.info/2014/12/html-munging-my-way-to-reactjs-conf.html); **James Long** blogged about [his first encounter with React Native](http://jlongster.com/First-Impressions-using-React-Native); **Eric Florenzano** talked about how he perceives the [impact of Relay, GraphQL, and React Native](https://medium.com/@ericflo/facebook-just-taught-us-all-how-to-build-websites-51f1e7e996f2) on software development; **Margaret Staples** blogged about her experience of [being on-campus at Facebook HQ](http://deadlugosi.blogspot.com/2015/02/facebook-gave-me-ice-cream.html); **Jeff Barczewski** tied his experience of attending the conference up with a bow in this [blog post filled with photos, videos, and links](http://codewinds.com/blog/2015-02-04-reactjs-conf.html); **Kevin Old** left us with [his takeaways](http://kevinold.com/2015/01/31/takeaways-from-reactjs-conf-2015.html); **Paul Wittmann** found React Native [freshly on his radar](http://www.railslove.com/stories/fresh-on-our-radar-react-native); and finally, undeterred by not being able to attend the conference in person, **Justin Ball** [summarized it from afar](http://www.justinball.com/2015/02/02/i-didn't-attend-react.js-conf.html).
And, in case you missed a session, you can borrow **Michael Chan’s** [drawings](http://chantastic.io/2015-reactjs-conf/), **Mihai Parparita’s** [summary](https://quip.com/uJQeABv7nkFN), or **Shaohua Zhou’s** [day 1](http://getshao.com/2015/01/29/react-js-conf-notes-day1/) / [day 2](http://getshao.com/2015/01/29/react-js-conf-notes-day-2/) notes.
@@ -266,4 +266,4 @@ And, in case you missed a session, you can borrow **Michael Chan’s** [drawings
**All proceeds from React.js Conf 2015 were donated to the wonderful programs at [code.org](http://code.org)**. These programs aim to increase access to the field of computer science by underrepresented members of our community. Watch this video to learn more.
There's more to building an application than creating a user interface. Data fetching is still a tricky problem, especially as applications become more complicated. At [React.js Conf](http://conf.reactjs.com/) we announced two projects we've created at Facebook to make data fetching simple for developers, even as a product grows to include dozens of contributors and the application becomes as complex as Facebook itself.
The two projects — Relay and GraphQL — have been in use in production at Facebook for some time, and we're excited to be bringing them to the world as open source in the future. In the meantime, we wanted to share some additional information about the projects here.
@@ -12,7 +12,7 @@ Interest in React has been exploding recently, so it's a good time to explore so
[Formidable Labs](https://github.com/FormidableLabs) and [Seattle JS](http://www.meetup.com/seattlejs/) recently hosted a series of React, Flux, and Flow workshops, and the first part is available to watch online:
[AEFlash](https://github.com/aearly) writes up [some best practices and tips](http://aeflash.com/2015-02/react-tips-and-best-practices.html) to help you avoid potential pitfalls when developing with React.
@@ -20,7 +20,7 @@ Black Mutt Media [takes us through their usage of React](http://blackmuttmedia.c
Our own [Sebastian Markbåge](https://github.com/sebmarkbage) was on the [Web Platform Podcast](http://thewebplatform.libsyn.com/31-building-with-reactjs) to have a chat about all aspects of React.
@@ -13,7 +13,7 @@ We open sourced React Native last week and the community reception blew away all
**Give us 6 months**. At Facebook, we strive to only open-source projects that we are using in production. While the Android backend for React Native is starting to work (see video below at 37min), it hasn't been shipped to any users yet. There's a lot of work that goes into open-sourcing a project, and we want to do it right so that you have a great experience when using it.
@@ -92,4 +92,3 @@ Clay Allsopp wrote a post about [all the crazy things you could do with a JavaSc
We've spent a lot of efforts getting the onboarding as easy as possible and we're really happy that people noticed. We still have a lot of work to do on documentation, stay tuned!
<blockquote class="twitter-tweet" lang="en"><p>Wow. Getting started with React Native might have been the smoothest experience I’ve ever had with a new developer product.</p>— Andreas Eldh (@eldh) <a href="https://twitter.com/eldh/status/581186172094980096">March 26, 2015</a></blockquote>
[Spencer Ahrens](https://github.com/sahrens) walks through building an advanced gestural UI leveraging the unique power of the React Native layout and animation systems to build a complex and fluid experience:
[Joseph Savona](https://github.com/josephsavona) explores the problems Relay solves, its architecture and the query lifecycle, and how can you use Relay to build more scalable apps. There are examples of how Relay powers applications as complex as the Facebook News Feed:
[Nick Schrock](https://github.com/schrockn) and [Dan Schafer](https://github.com/dschafer) take a deeper dive into putting GraphQL to work. How can we build a GraphQL API to work with an existing REST API or server-side data model? What are best practices when building a GraphQL API, and how do they differ from traditional REST best practices? How does Facebook use GraphQL? Most importantly, what does a complete and coherent GraphQL API looks like, and how can we get started building one?
[Sebastian Markbåge](https://github.com/sebmarkbage) talks about why the DOM is flawed and how it is becoming a second-class citizen in the land of React apps:
[Sebastian McKenzie](https://github.com/sebmck) goes over how existing JSX build pipeline infrastructure can be further utilised to perform even more significant code transformations such as transpilation, optimisation, profiling and more, reducing bugs, making your code faster and you as a developer more productive and happy:
[Cheng Lou](https://github.com/chenglou) gives a talk on the past, the present and the future of animation, and the place React can potentially take in this:
We would like to thank the React community for reporting issues and regressions in the release candidates on our [issue tracker](https://github.com/facebook/react/issues/). Over the last few weeks we fixed those issues, and now, after two release candidates, we are excited to finally release the stable version of React 15.
As a reminder, [we’re switching to major versions](/react/blog/2016/02/19/new-versioning-scheme.html) to indicate that we have been using React in production for a long time. This 15.0 release follows our previous 0.14 version and we’ll continue to follow semver like we’ve been doing since 2013. It’s also worth noting that [we no longer actively support Internet Explorer 8](/react/blog/2016/01/12/discontinuing-ie8-support.html). We believe React will work in its current form there but we will not be prioritizing any efforts to fix new issues that only affect IE8.
React 15 brings significant improvements to how we interact with the DOM:
* We are now using `document.createElement` instead of setting `innerHTML` when mounting components. This allows us to get rid of the `data-reactid` attribute on every node and make the DOM lighter. Using `document.createElement` is also faster in modern browsers and fixes a number of edge cases related to SVG elements and running multiple copies of React on the same page.
* Historically our support for SVG has been incomplete, and many tags and attributes were missing. We heard you, and in React 15 we [added support for all the SVG attributes that are recognized by today’s browsers](https://github.com/facebook/react/pull/6243). If we missed any of the attributes you’d like to use, please [let us know](https://github.com/facebook/react/issues/1657). As a bonus, thanks to using `document.createElement`, we no longer need to maintain a list of SVG tags, so any SVG tags that were previously unsupported should work just fine in React 15.
* We received some amazing contributions from the community in this release, and we would like to highlight [this pull request](https://github.com/facebook/react/pull/5753) by [Michael Wiencek](https://github.com/mwiencek) in particular. Thanks to Michael’s work, React 15 no longer emits extra `<span>` nodes around the text, making the DOM output much cleaner. This was a longstanding annoyance for React users so it’s exciting to accept this as an outside contribution.
While this isn’t directly related to the release, we understand that in order to receive more community contributions like Michael’s, we need to communicate our goals and priorities more openly, and review pull requests more decisively. As a first step towards this, we started publishing [React core team weekly meeting notes](https://github.com/reactjs/core-notes) again. We also intend to introduce an RFC process inspired by [Ember RFCs](https://github.com/emberjs/rfcs) so external contributors can have more insight and influence in the future development of React. We will keep you updated about this on our blog.
We are also experimenting with a new changelog format in this post. Every change now links to the corresponding pull request and mentions the author. Let us know whether you find this useful!
## Upgrade Guide
As usual with major releases, React 15 will remove support for some of the patterns deprecated nine months ago in React 0.14. We know changes can be painful (the Facebook codebase has over 20,000 React components, and that’s not even counting React Native), so we always try to make changes gradually in order to minimize the pain.
If your code is free of warnings when running under React 0.14, upgrading should be easy. The bulk of changes in this release are actually behind the scenes, impacting the way that React interacts with the DOM. The other substantial change is that React now supports the full range of SVG elements and attributes. Beyond that we have a large number of incremental improvements and additional warnings aimed to aid developers. We’ve also laid some groundwork in the core to bring you some new capabilities in future releases.
See the changelog below for more details.
## Installation
We recommend using React from `npm` and using a tool like browserify or webpack to build your code into a single bundle. To install the two packages:
*`npm install --save react react-dom`
Remember that by default, React runs extra checks and provides helpful warnings in development mode. When deploying your app, set the `NODE_ENV` environment variable to `production` to use the production build of React which does not include the development warnings and runs significantly faster.
If you can’t use `npm` yet, we provide pre-built browser builds for your convenience, which are also available in the `react` package on bower.
* **React**
Dev build with warnings: <https://fb.me/react-15.0.0.js>
Minified build for production: <https://fb.me/react-15.0.0.min.js>
***React with Add-Ons**
Dev build with warnings: <https://fb.me/react-with-addons-15.0.0.js>
Minified build for production: <https://fb.me/react-with-addons-15.0.0.min.js>
***React DOM** (include React in the page before React DOM)
Dev build with warnings: <https://fb.me/react-dom-15.0.0.js>
Minified build for production: <https://fb.me/react-dom-15.0.0.min.js>
## Changelog
### Major changes
- #### `document.createElement` is in and `data-reactid` is out
There were a number of large changes to our interactions with the DOM. One of the most noticeable changes is that we no longer set the `data-reactid` attribute for each DOM node. While this will make it more difficult to know if a website is using React, the advantage is that the DOM is much more lightweight. This change was made possible by us switching to use `document.createElement` on initial render. Previously we would generate a large string of HTML and then set `node.innerHTML`. At the time, this was decided to be faster than using `document.createElement` for the majority of cases and browsers that we supported. Browsers have continued to improve and so overwhelmingly this is no longer true. By using `createElement` we can make other parts of React faster. The ids were used to map back from events to the original React component, meaning we had to do a bunch of work on every event, even though we cached this data heavily. As we’ve all experienced, caching and in particularly invalidating caches, can be error prone and we saw many hard to reproduce issues over the years as a result. Now we can build up a direct mapping at render time since we already have a handle on the node.
**Note:**`data-reactid` is still present for server-rendered content, however it is much smaller than before and is simply an auto-incrementing counter.
<small>[@spicyj](https://github.com/spicyj) in [#5205](https://github.com/facebook/react/pull/5205)</small>
- #### No more extra `<span>`s
Another big change with our DOM interaction is how we render text blocks. Previously you may have noticed that React rendered a lot of extra `<span>`s. For example, in our most basic example on the home page we render `<div>Hello {this.props.name}</div>`, resulting in markup that contained 2 `<span>`s. Now we’ll render plain text nodes interspersed with comment nodes that are used for demarcation. This gives us the same ability to update individual pieces of text, without creating extra nested nodes. Very few people have depended on the actual markup generated here so it’s likely you are not impacted. However if you were targeting these `<span>`s in your CSS, you will need to adjust accordingly. You can always render them explicitly in your components.
<small>[@mwiencek](https://github.com/mwiencek) in [#5753](https://github.com/facebook/react/pull/5753)</small>
- #### Rendering `null` now uses comment nodes
We’ve also made use of these comment nodes to change what `null` renders to. Rendering to `null` was a feature we added in React 0.11 and was implemented by rendering `<noscript>` elements. By rendering to comment nodes now, there’s a chance some of your CSS will be targeting the wrong thing, specifically if you are making use of `:nth-child` selectors. React’s use of the `<noscript>` tag has always been considered an implementation detail of how React targets the DOM. We believe they are safe changes to make without going through a release with warnings detailing the subtle differences as they are details that should not be depended upon. Additionally, we have seen that these changes have improved React performance for many typical applications.
<small>[@spicyj](https://github.com/spicyj) in [#5451](https://github.com/facebook/react/pull/5451)</small>
- #### Functional components can now return `null` too
We added support for [defining stateless components as functions](/react/blog/2015/09/10/react-v0.14-rc1.html#stateless-function-components) in React 0.14. However, React 0.14 still allowed you to define a class component without extending `React.Component` or using `React.createClass()`, so [we couldn’t reliably tell if your component is a function or a class](https://github.com/facebook/react/issues/5355), and did not allow returning `null` from it. This issue is solved in React 15, and you can now return `null` from any component, whether it is a class or a function.
<small>[@jimfb](https://github.com/jimfb) in [#5884](https://github.com/facebook/react/pull/5884)</small>
- #### Improved SVG support
All SVG tags are now fully supported. (Uncommon SVG tags are not present on the `React.DOM` element helper, but JSX and `React.createElement` work on all tag names.) All SVG attributes that are implemented by the browsers should be supported too. If you find any attributes that we have missed, please [let us know in this issue](https://github.com/facebook/react/issues/1657).
<small>[@zpao](https://github.com/zpao) in [#6243](https://github.com/facebook/react/pull/6243)</small>
### Breaking changes
- #### No more extra `<span>`s
It’s worth calling out the DOM structure changes above again, in particular the change from `<span>`s. In the course of updating the Facebook codebase, we found a very small amount of code that was depending on the markup that React generated. Some of these cases were integration tests like WebDriver which were doing very specific XPath queries to target nodes. Others were simply tests using `ReactDOM.renderToStaticMarkup` and comparing markup. Again, there were a very small number of changes that had to be made, but we don’t want anybody to be blindsided. We encourage everybody to run their test suites when upgrading and consider alternative approaches when possible. One approach that will work for some cases is to explicitly use `<span>`s in your `render` method.
<small>[@mwiencek](https://github.com/mwiencek) in [#5753](https://github.com/facebook/react/pull/5753)</small>
- #### `React.cloneElement()` now resolves `defaultProps`
We fixed a bug in `React.cloneElement()` that some components may rely on. If some of the `props` received by `cloneElement()` are `undefined`, it used to return an element with `undefined` values for those props. In React 15, we’re changing it to be consistent with `createElement()`. Now any `undefined` props passed to `cloneElement()` are resolved to the corresponding component’s `defaultProps`. Only one of our 20,000 React components was negatively affected by this so we feel comfortable releasing this change without keeping the old behavior for another release cycle.
<small>[@truongduy134](https://github.com/truongduy134) in [#5997](https://github.com/facebook/react/pull/5997)</small>
- #### `ReactPerf.getLastMeasurements()` is opaque
This change won’t affect applications but may break some third-party tools. We are [revamping `ReactPerf` implementation](https://github.com/facebook/react/pull/6046) and plan to release it during the 15.x cycle. The internal performance measurement format is subject to change so, for the time being, we consider the return value of `ReactPerf.getLastMeasurements()` an opaque data structure that should not be relied upon.
<small>[@gaearon](https://github.com/gaearon) in [#6286](https://github.com/facebook/react/pull/6286)</small>
- #### Removed deprecations
These deprecations were introduced nine months ago in v0.14 with a warning and are removed:
- Deprecated APIs are removed from the `React` top-level export: `findDOMNode`, `render`, `renderToString`, `renderToStaticMarkup`, and `unmountComponentAtNode`. As a reminder, they are now available on `ReactDOM` and `ReactDOMServer`.
<small>[@jimfb](https://github.com/jimfb) in [#5832](https://github.com/facebook/react/pull/5832)</small>
- Deprecated addons are removed: `batchedUpdates` and `cloneWithProps`.
<small>[@jimfb](https://github.com/jimfb) in [#5859](https://github.com/facebook/react/pull/5859), [@zpao](https://github.com/zpao) in [#6016](https://github.com/facebook/react/pull/6016)</small>
- Deprecated component instance methods are removed: `setProps`, `replaceProps`, and `getDOMNode`.
<small>[@jimfb](https://github.com/jimfb) in [#5570](https://github.com/facebook/react/pull/5570)</small>
- Deprecated CommonJS `react/addons` entry point is removed. As a reminder, you should use separate `react-addons-*` packages instead. This only applies if you use the CommonJS builds.
<small>[@gaearon](https://github.com/gaearon) in [#6285](https://github.com/facebook/react/pull/6285)</small>
- Passing `children` to void elements like `<input>` was deprecated, and now throws an error.
<small>[@jonhester](https://github.com/jonhester) in [#3372](https://github.com/facebook/react/pull/3372)</small>
- React-specific properties on DOM `refs` (e.g. `this.refs.div.props`) were deprecated, and are removed now.
<small>[@jimfb](https://github.com/jimfb) in [#5495](https://github.com/facebook/react/pull/5495)</small>
### New deprecations, introduced with a warning
Each of these changes will continue to work as before with a new warning until the release of React 16 so you can upgrade your code gradually.
-`LinkedStateMixin` and `valueLink` are now deprecated due to very low popularity. If you need this, you can use a wrapper component that implements the same behavior: [react-linked-input](https://www.npmjs.com/package/react-linked-input).
<small>[@jimfb](https://github.com/jimfb) in [#6127](https://github.com/facebook/react/pull/6127)</small>
- Future versions of React will treat `<input value={null}>` as a request to clear the input. However, React 0.14 has been ignoring `value={null}`. React 15 warns you on a `null` input value and offers you to clarify your intention. To fix the warning, you may explicitly pass an empty string to clear a controlled input, or pass `undefined` to make the input uncontrolled.
<small>[@antoaravinth](https://github.com/antoaravinth) in [#5048](https://github.com/facebook/react/pull/5048)</small>
-`ReactPerf.printDOM()` was renamed to `ReactPerf.printOperations()`, and `ReactPerf.getMeasurementsSummaryMap()` was renamed to `ReactPerf.getWasted()`.
<small>[@gaearon](https://github.com/gaearon) in [#6287](https://github.com/facebook/react/pull/6287)</small>
### New helpful warnings
- If you use a minified copy of the _development_ build, React DOM kindly encourages you to use the faster production build instead.
<small>[@spicyj](https://github.com/spicyj) in [#5083](https://github.com/facebook/react/pull/5083)</small>
- React DOM: When specifying a unit-less CSS value as a string, a future version will not add `px` automatically. This version now warns in this case (ex: writing `style={{'{{'}}width: '300'}}`. Unitless *number* values like `width: 300` are unchanged.
<small>[@pluma](https://github.com/pluma) in [#5140](https://github.com/facebook/react/pull/5140)</small>
- Synthetic Events will now warn when setting and accessing properties (which will not get cleared appropriately), as well as warn on access after an event has been returned to the pool.
<small>[@kentcdodds](https://github.com/kentcdodds) in [#5940](https://github.com/facebook/react/pull/5940) and [@koba04](https://github.com/koba04) in [#5947](https://github.com/facebook/react/pull/5947)</small>
- Elements will now warn when attempting to read `ref` and `key` from the props.
<small>[@prometheansacrifice](https://github.com/prometheansacrifice) in [#5744](https://github.com/facebook/react/pull/5744)</small>
- React will now warn if you pass a different `props` object to `super()` in the constructor.
<small>[@prometheansacrifice](https://github.com/prometheansacrifice) in [#5346](https://github.com/facebook/react/pull/5346)</small>
- React will now warn if you call `setState()` inside `getChildContext()`.
<small>[@raineroviir](https://github.com/raineroviir) in [#6121](https://github.com/facebook/react/pull/6121)</small>
- React DOM now attempts to warn for mistyped event handlers on DOM elements, such as `onclick` which should be `onClick`.
<small>[@ali](https://github.com/ali) in [#5361](https://github.com/facebook/react/pull/5361)</small>
- React DOM now warns about `NaN` values in `style`.
<small>[@jontewks](https://github.com/jontewks) in [#5811](https://github.com/facebook/react/pull/5811)</small>
- React DOM now warns if you specify both `value` and `defaultValue` for an input.
<small>[@mgmcdermott](https://github.com/mgmcdermott) in [#5823](https://github.com/facebook/react/pull/5823)</small>
- React DOM now warns if an input switches between being controlled and uncontrolled.
<small>[@TheBlasfem](https://github.com/TheBlasfem) in [#5864](https://github.com/facebook/react/pull/5864)</small>
- React DOM now warns if you specify `onFocusIn` or `onFocusOut` handlers as they are unnecessary in React.
<small>[@jontewks](https://github.com/jontewks) in [#6296](https://github.com/facebook/react/pull/6296)</small>
- React now prints a descriptive error message when you pass an invalid callback as the last argument to `ReactDOM.render()`, `this.setState()`, or `this.forceUpdate()`.
<small>[@conorhastings](https://github.com/conorhastings) in [#5193](https://github.com/facebook/react/pull/5193) and [@gaearon](https://github.com/gaearon) in [#6310](https://github.com/facebook/react/pull/6310)</small>
- Add-Ons: `TestUtils.Simulate()` now prints a helpful message if you attempt to use it with shallow rendering.
<small>[@conorhastings](https://github.com/conorhastings) in [#5358](https://github.com/facebook/react/pull/5358)</small>
- PropTypes: `arrayOf()` and `objectOf()` provide better error messages for invalid arguments.
<small>[@chicoxyzzy](https://github.com/chicoxyzzy) in [#5390](https://github.com/facebook/react/pull/5390)</small>
### Notable bug fixes
- Fixed multiple small memory leaks.
<small>[@spicyj](https://github.com/spicyj) in [#4983](https://github.com/facebook/react/pull/4983) and [@victor-homyakov](https://github.com/victor-homyakov) in [#6309](https://github.com/facebook/react/pull/6309)</small>
- Input events are handled more reliably in IE 10 and IE 11; spurious events no longer fire when using a placeholder.
<small>[@jquense](https://github.com/jquense) in [#4051](https://github.com/facebook/react/pull/4051)</small>
- The `componentWillReceiveProps()` lifecycle method is now consistently called when `context` changes.
<small>[@milesj](https://github.com/milesj) in [#5787](https://github.com/facebook/react/pull/5787)</small>
-`React.cloneElement()` doesn’t append slash to an existing `key` when used inside `React.Children.map()`.
<small>[@ianobermiller](https://github.com/ianobermiller) in [#5892](https://github.com/facebook/react/pull/5892)</small>
- React DOM now supports the `cite` and `profile` HTML attributes.
<small>[@AprilArcus](https://github.com/AprilArcus) in [#6094](https://github.com/facebook/react/pull/6094) and [@saiichihashimoto](https://github.com/saiichihashimoto) in [#6032](https://github.com/facebook/react/pull/6032)</small>
- React DOM now supports `cssFloat`, `gridRow` and `gridColumn` CSS properties.
<small>[@stevenvachon](https://github.com/stevenvachon) in [#6133](https://github.com/facebook/react/pull/6133) and [@mnordick](https://github.com/mnordick) in [#4779](https://github.com/facebook/react/pull/4779)</small>
- React DOM now correctly handles `borderImageOutset`, `borderImageWidth`, `borderImageSlice`, `floodOpacity`, `strokeDasharray`, and `strokeMiterlimit` as unitless CSS properties.
<small>[@rofrischmann](https://github.com/rofrischmann) in [#6210](https://github.com/facebook/react/pull/6210) and [#6270](https://github.com/facebook/react/pull/6270)</small>
- React DOM now supports the `onAnimationStart`, `onAnimationEnd`, `onAnimationIteration`, `onTransitionEnd`, and `onInvalid` events. Support for `onLoad` has been added to `object` elements.
<small>[@tomduncalf](https://github.com/tomduncalf) in [#5187](https://github.com/facebook/react/pull/5187), [@milesj](https://github.com/milesj) in [#6005](https://github.com/facebook/react/pull/6005), and [@ara4n](https://github.com/ara4n) in [#5781](https://github.com/facebook/react/pull/5781)</small>
- React DOM now defaults to using DOM attributes instead of properties, which fixes a few edge case bugs. Additionally the nullification of values (ex: `href={null}`) now results in the forceful removal, no longer trying to set to the default value used by browsers in the absence of a value.
<small>[@syranide](https://github.com/syranide) in [#1510](https://github.com/facebook/react/pull/1510)</small>
- React DOM does not mistakingly coerce `children` to strings for Web Components.
<small>[@jimfb](https://github.com/jimfb) in [#5093](https://github.com/facebook/react/pull/5093)</small>
- React DOM now correctly normalizes SVG `<use>` events.
<small>[@edmellum](https://github.com/edmellum) in [#5720](https://github.com/facebook/react/pull/5720)</small>
- React DOM does not throw if a `<select>` is unmounted while its `onChange` handler is executing.
<small>[@sambev](https://github.com/sambev) in [#6028](https://github.com/facebook/react/pull/6028)</small>
- React DOM does not throw in Windows 8 apps.
<small>[@Andrew8xx8](https://github.com/Andrew8xx8) in [#6063](https://github.com/facebook/react/pull/6063)</small>
- React DOM does not throw when asynchronously unmounting a child with a `ref`.
<small>[@yiminghe](https://github.com/yiminghe) in [#6095](https://github.com/facebook/react/pull/6095)</small>
- React DOM no longer forces synchronous layout because of scroll position tracking.
<small>[@syranide](https://github.com/syranide) in [#2271](https://github.com/facebook/react/pull/2271)</small>
-`Object.is` is used in a number of places to compare values, which leads to fewer false positives, especially involving `NaN`. In particular, this affects the `shallowCompare` add-on.
<small>[@chicoxyzzy](https://github.com/chicoxyzzy) in [#6132](https://github.com/facebook/react/pull/6132)</small>
- Add-Ons: ReactPerf no longer instruments adding or removing an event listener because they don’t really touch the DOM due to event delegation.
<small>[@antoaravinth](https://github.com/antoaravinth) in [#5209](https://github.com/facebook/react/pull/5209)</small>
###Other improvements
- React now uses `loose-envify` instead of `envify` so it installs fewer transitive dependencies.
<small>[@qerub](https://github.com/qerub) in [#6303](https://github.com/facebook/react/pull/6303)</small>
- Shallow renderer now exposes `getMountedInstance()`.
<small>[@glenjamin](https://github.com/glenjamin) in [#4918](https://github.com/facebook/react/pull/4918)</small>
- Shallow renderer now returns the rendered output from `render()`.
<small>[@simonewebdesign](https://github.com/simonewebdesign) in [#5411](https://github.com/facebook/react/pull/5411)</small>
- React no longer depends on ES5 *shams* for `Object.create` and `Object.freeze` in older environments. It still, however, requires ES5 *shims* in those environments.
<small>[@dgreensp](https://github.com/dgreensp) in [#4959](https://github.com/facebook/react/pull/4959)</small>
- React DOM now allows `data-` attributes with names that start with numbers.
<small>[@nLight](https://github.com/nLight) in [#5216](https://github.com/facebook/react/pull/5216)</small>
- React DOM adds a new `suppressContentEditableWarning` prop for components like [Draft.js](https://facebook.github.io/draft-js/) that intentionally manage `contentEditable` children with React.
<small>[@mxstbr](https://github.com/mxstbr) in [#6112](https://github.com/facebook/react/pull/6112)</small>
- React improves the performance for `createClass()` on complex specs.
<small>[@spicyj](https://github.com/spicyj) in [#5550](https://github.com/facebook/react/pull/5550)</small>
Yesterday afternoon we shipped v15.0.0 and quickly got some feedback about a couple of issues. We apologize for these problems and we've been working since then to make sure we get fixes into your hands as quickly as possible.
The first of these issues is related to the removal of an undocumented API. This API was added to enable [JSX Spread Attributes](/react/docs/jsx-spread.html) in our JS compile tools (react-tools, JSXTransformer) before `Object.assign` was standard. When we stopped supporting these tools last year, we kept the API there to catch the longer tail of people using those tools. Meanwhile we moved to using Babel and encouraged others to do the same. Babel will typically compile the spread use to an `_extends` helper, which will use `Object.assign`. We did not properly research other compilation tools before deciding to remove the API in v15. Specifically, TypeScript and coffee-react are two popular packages using `React.__spread`, as well as reactify which still makes use react-tools. In order to make sure that code compiled with these tools is not broken, we will be restoring the `React.__spread` API and adding a warning. It will be removed in the future so if you maintain a project making using of it, we encourage you to compile to `Object.assign` directly or a similar helper function.
The second issue resulted in cursor position being lost in controlled inputs. We merged a pull request earlier this week to fix a separate regression from v0.14. Our goal was to target `<option>` elements but we ended up targeting all interactions with `value` properties. Unfortunately we didn't test it as thoroughly as we thought. We backed out the offending change and fixed the issue in different way which doesn't have the same problem.
We apologize if you installed 15.0.0 and have encountered these issues yourselves.
As usual, you can get install the `react` package via npm or download a browser bundle.
* **React**
Dev build with warnings: <https://fb.me/react-15.0.1.js>
Minified build for production: <https://fb.me/react-15.0.1.min.js>
***React with Add-Ons**
Dev build with warnings: <https://fb.me/react-with-addons-15.0.1.js>
Minified build for production: <https://fb.me/react-with-addons-15.0.1.min.js>
***React DOM** (include React in the page before React DOM)
Dev build with warnings: <https://fb.me/react-dom-15.0.1.js>
Minified build for production: <https://fb.me/react-dom-15.0.1.min.js>
## Changelog
### React
- Restore `React.__spread` API to unbreak code compiled with some tools making use of this undocumented API. It is now officially deprecated.
<small>[@zpao](https://github.com/zpao) in [#6444](https://github.com/facebook/react/pull/6444)</small>
### ReactDOM
- Fixed issue resulting in loss of cursor position in controlled inputs.
<small>[@spicyj](https://github.com/spicyj) in [#6449](https://github.com/facebook/react/pull/6449)</small>
Building a better developer experience has been one of the things that React deeply cares about, and a crucial part of it is to detect anti-patterns/potential errors early and provide helpful error messages when things (may) go wrong. However, most of these only exist in development mode; in production, we avoid having extra expensive assertions and sending down full error messages in order to reduce the number of bytes sent over the wire.
Prior to this release, we stripped out error messages at build-time and this is why you might have seen this message in production:
> Minified exception occurred; use the non-minified dev environment for the full error message and additional helpful warnings.
In order to make debugging in production easier, we're introducing an Error Code System in [15.2.0](https://github.com/facebook/react/releases/tag/v15.2.0). We developed a [gulp script](https://github.com/facebook/react/blob/master/scripts/error-codes/gulp-extract-errors.js) that collects all of our `invariant` error messages and folds them to a [JSON file](https://github.com/facebook/react/blob/master/scripts/error-codes/codes.json), and at build-time Babel uses the JSON to [rewrite](https://github.com/facebook/react/blob/master/scripts/error-codes/dev-expression-with-codes.js) our `invariant` calls in production to reference the corresponding error IDs. Now when things go wrong in production, the error that React throws will contain a URL with an error ID and relevant information. The URL will point you to a page in our documentation where the original error message gets reassembled.
While we hope you don't see errors often, you can see how it works [here](/react/docs/error-decoder.html?invariant=109&args[]=Foo). This is what the same error from above will look like:
> Minified React error #109; visit https://facebook.github.io/react/docs/error-decoder.html?invariant=109&args[]=Foo for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
We do this so that the developer experience is as good as possible, while also keeping the production bundle size as small as possible. This feature shouldn't require any changes on your side — use the `min.js` files in production or bundle your application code with `process.env.NODE_ENV === 'production'` and you should be good to go!
“How do I share the code between several components?” is one of the first questions that people ask when they learn React. Our answer has always been to use component composition for code reuse. You can define a component and use it in several other components.
It is not always obvious how a certain pattern can be solved with composition. React is influenced by functional programming but it came into the field that was dominated by object-oriented libraries. It was hard for engineers both inside and outside of Facebook to give up on the patterns they were used to.
To ease the initial adoption and learning, we included certain escape hatches into React. The mixin system was one of those escape hatches, and its goal was to give you a way to reuse code between components when you aren’t sure how to solve the same problem with composition.
Three years passed since React was released. The landscape has changed. Multiple view libraries now adopt a component model similar to React. Using composition over inheritance to build declarative user interfaces is no longer a novelty. We are also more confident in the React component model, and we have seen many creative uses of it both internally and in the community.
In this post, we will consider the problems commonly caused by mixins. Then we will suggest several alternative patterns for the same use cases. We have found those patterns to scale better with the complexity of the codebase than mixins.
## Why Mixins are Broken
At Facebook, React usage has grown from a few components to thousands of them. This gives us a window into how people use React. Thanks to declarative rendering and top-down data flow, many teams were able to fix a bunch of bugs while shipping new features as they adopted React.
However it’s inevitable that some of our code using React gradually became incomprehensible. Occasionally, the React team would see groups of components in different projects that people were afraid to touch. These components were too easy to break accidentally, were confusing to new developers, and eventually became just as confusing to the people who wrote them in the first place. Much of this confusion was caused by mixins. At the time, I wasn’t working at Facebook but I came to the [same conclusions](https://medium.com/@dan_abramov/mixins-are-dead-long-live-higher-order-components-94a0d2f9e750) after writing my fair share of terrible mixins.
This doesn’t mean that mixins themselves are bad. People successfully employ them in different languages and paradigms, including some functional languages. At Facebook, we extensively use traits in Hack which are fairly similar to mixins. Nevertheless, we think that mixins are unnecessary and problematic in React codebases. Here’s why.
### Mixins introduce implicit dependencies
Sometimes a component relies on a certain method defined in the mixin, such as `getClassName()`. Sometimes it’s the other way around, and mixin calls a method like `renderHeader()` on the component. JavaScript is a dynamic language so it’s hard to enforce or document these dependencies.
Mixins break the common and usually safe assumption that you can rename a state key or a method by searching for its occurrences in the component file. You might write a stateful component and then your coworker might add a mixin that reads this state. In a few months, you might want to move that state up to the parent component so it can be shared with a sibling. Will you remember to update the mixin to read a prop instead? What if, by now, other components also use this mixin?
These implicit dependencies make it hard for new team members to contribute to a codebase. A component’s `render()` method might reference some method that isn’t defined on the class. Is it safe to remove? Perhaps it’s defined in one of the mixins. But which one of them? You need to scroll up to the mixin list, open each of those files, and look for this method. Worse, mixins can specify their own mixins, so the search can be deep.
Often, mixins come to depend on other mixins, and removing one of them breaks the other. In these situations it is very tricky to tell how the data flows in and out of mixins, and what their dependency graph looks like. Unlike components, mixins don’t form a hierarchy: they are flattened and operate in the same namespace.
### Mixins cause name clashes
There is no guarantee that two particular mixins can be used together. For example, if `FluxListenerMixin` defines `handleChange()` and `WindowSizeMixin` defines `handleChange()`, you can’t use them together. You also can’t define a method with this name on your own component.
It’s not a big deal if you control the mixin code. When you have a conflict, you can rename that method on one of the mixins. However it’s tricky because some components or other mixins may already be calling this method directly, and you need to find and fix those calls as well.
If you have a name conflict with a mixin from a third party package, you can’t just rename a method on it. Instead, you have to use awkward method names on your component to avoid clashes.
The situation is no better for mixin authors. Even adding a new method to a mixin is always a potentially breaking change because a method with the same name might already exist on some of the components using it, either directly or through another mixin. Once written, mixins are hard to remove or change. Bad ideas don’t get refactored away because refactoring is too risky.
### Mixins cause snowballing complexity
Even when mixins start out simple, they tend to become complex over time. The example below is based on a real scenario I’ve seen play out in a codebase.
A component needs some state to track mouse hover. To keep this logic reusable, you might extract `handleMouseEnter()`, `handleMouseLeave()` and `isHovering()` into a `HoverMixin`. Next, somebody needs to implement a tooltip. They don’t want to duplicate the logic in `HoverMixin` so they create a `TooltipMixin` that uses `HoverMixin`. `TooltipMixin` reads `isHovering()` provided by `HoverMixin` in its `componentDidUpdate()` and either shows or hides the tooltip.
A few months later, somebody wants to make the tooltip direction configurable. In an effort to avoid code duplication, they add support for a new optional method called `getTooltipOptions()` to `TooltipMixin`. By this time, components that show popovers also use `HoverMixin`. However popovers need a different hover delay. To solve this, somebody adds support for an optional `getHoverOptions()` method and implements it in `TooltipMixin`. Those mixins are now tightly coupled.
This is fine while there are no new requirements. However this solution doesn’t scale well. What if you want to support displaying multiple tooltips in a single component? You can’t define the same mixin twice in a component. What if the tooltips need to be displayed automatically in a guided tour instead of on hover? Good luck decoupling `TooltipMixin` from `HoverMixin`. What if you need to support the case where the hover area and the tooltip anchor are located in different components? You can’t easily hoist the state used by mixin up into the parent component. Unlike components, mixins don’t lend themselves naturally to such changes.
Every new requirement makes the mixins harder to understand. Components using the same mixin become increasingly coupled with time. Any new capability gets added to all of the components using that mixin. There is no way to split a “simpler” part of the mixin without either duplicating the code or introducing more dependencies and indirection between mixins. Gradually, the encapsulation boundaries erode, and since it’s hard to change or remove the existing mixins, they keep getting more abstract until nobody understands how they work.
These are the same problems we faced building apps before React. We found that they are solved by declarative rendering, top-down data flow, and encapsulated components. At Facebook, we have been migrating our code to use alternative patterns to mixins, and we are generally happy with the results. You can read about those patterns below.
## Migrating from Mixins
Let’s make it clear that mixins are not technically deprecated. If you use `React.createClass()`, you may keep using them. We only say that they didn’t work well for us, and so we won’t recommend using them in the future.
Every section below corresponds to a mixin usage pattern that we found in the Facebook codebase. For each of them, we describe the problem and a solution that we think works better than mixins. The examples are written in ES5 but once you don’t need mixins, you can switch to ES6 classes if you’d like.
We hope that you find this list helpful. Please let us know if we missed important use cases so we can either amend the list or be proven wrong!
### Performance Optimizations
One of the most commonly used mixins is [`PureRenderMixin`](/react/docs/pure-render-mixin.html). You might be using it in some components to [prevent unnecessary re-renders](/react/docs/advanced-performance.html#shouldcomponentupdate-in-action) when the props and state are shallowly equal to the previous props and state:
If you use a custom mixin implementing a `shouldComponentUpdate` function with different algorithm, we suggest exporting just that single function from a module and calling it directly from your components.
We understand that more typing can be annoying. For the most common case, we plan to [introduce a new base class](https://github.com/facebook/react/pull/7195) called `React.PureComponent` in the next minor release. It uses the same shallow comparison as `PureRenderMixin` does today.
### Subscriptions and Side Effects
The second most common type of mixins that we encountered are mixins that subscribe a React component to a third-party data source. Whether this data source is a Flux Store, an Rx Observable, or something else, the pattern is very similar: the subscription is created in `componentDidMount`, destroyed in `componentWillUnmount`, and the change handler calls `this.setState()`.
If there is just one component subscribed to this data source, it is fine to embed the subscription logic right into the component. Avoid premature abstractions.
If several components used this mixin to subscribe to a data source, a nice way to avoid repetition is to use a pattern called [“higher-order components”](https://medium.com/@dan_abramov/mixins-are-dead-long-live-higher-order-components-94a0d2f9e750). It can sound intimidating so we will take a closer look at how this pattern naturally emerges from the component model.
#### Higher-Order Components Explained
Let’s forget about React for a second. Consider these two functions that add and multiply numbers, logging the results as they do that:
```js
functionaddAndLog(x,y){
varresult=x+y;
console.log('result:',result);
returnresult;
}
functionmultiplyAndLog(x,y){
varresult=x*y;
console.log('result:',result);
returnresult;
}
```
These two functions are not very useful but they help us demonstrate a pattern that we can later apply to components.
Let’s say that we want to extract the logging logic out of these functions without changing their signatures. How can we do this? An elegant solution is to write a [higher-order function](https://en.wikipedia.org/wiki/Higher-order_function), that is, a function that takes a function as an argument and returns a function.
Again, it sounds more intimidating than it really is:
```js
functionwithLogging(wrappedFunction){
// Return a function with the same API...
returnfunction(x,y){
// ... that calls the original function
varresult=wrappedFunction(x,y);
// ... but also logs its result!
console.log('result:',result);
returnresult;
};
}
```
The `withLogging` higher-order function lets us write `add` and `multiply` without the logging statements, and later wrap them to get `addAndLog` and `multiplyAndLog` with exactly the same signatures as before:
```js
functionadd(x,y){
returnx+y;
}
functionmultiply(x,y){
returnx*y;
}
functionwithLogging(wrappedFunction){
returnfunction(x,y){
varresult=wrappedFunction(x,y);
console.log('result:',result);
returnresult;
};
}
// Equivalent to writing addAndLog by hand:
varaddAndLog=withLogging(add);
// Equivalent to writing multiplyAndLog by hand:
varmultiplyAndLog=withLogging(multiply);
```
Higher-order components are a very similar pattern, but applied to components in React. We will apply this transformation from mixins in two steps.
As a first step, we will split our `CommentList` component in two, a child and a parent. The child will be only concerned with rendering the comments. The parent will set up the subscription and pass the up-to-date data to the child via props.
```js
// This is a child component.
// It only renders the comments it receives as props.
varCommentList=React.createClass({
render:function(){
// Note: now reading from props rather than state.
varcomments=this.props.comments;
return(
<div>
{comments.map(function(comment){
return<Commentcomment={comment}key={comment.id}/>
})}
</div>
)
}
});
// This is a parent component.
// It subscribes to the data source and renders <CommentList />.
Remember how we made `withLogging()` take a function and return another function wrapping it? We can apply a similar pattern to React components.
We will write a new function called `withSubscription(WrappedComponent)`. Its argument could be any React component. We will pass `CommentList` as `WrappedComponent`, but we could also apply `withSubscription()` to any other component in our codebase.
This function would return another component. The returned component would manage the subscription and render `<WrappedComponent />` with the current data.
We call this pattern a “higher-order component”.
The composition happens at React rendering level rather than with a direct function call. This is why it doesn’t matter whether the wrapped component is defined with `createClass()`, as an ES6 class or a function. If `WrappedComponent` is a React component, the component created by `withSubscription()` can render it.
// The rest of the app is interested in the subscribed component
// so we export it instead of the original unwrapped CommentList.
module.exports=CommentListWithSubscription;
```
#### Solution, Revisited
Now that we understand higher-order components better, let’s take another look at the complete solution that doesn’t involve mixins. There are a few minor changes that are annotated with inline comments:
// Optional change: convert CommentList to a functional component
// because it doesn't use lifecycle hooks or state.
functionCommentList(props){
varcomments=props.comments;
return(
<div>
{comments.map(function(comment){
return<Commentcomment={comment}key={comment.id}/>
})}
</div>
)
}
// Instead of declaring CommentListWithSubscription,
// we export the wrapped component right away.
module.exports=withSubscription(CommentList);
```
Higher-order components are a powerful pattern. You can pass additional arguments to them if you want to further customize their behavior. After all, they are not even a feature of React. They are just functions that receive components and return components that wrap them.
Like any solution, higher-order components have their own pitfalls. For example, if you heavily use [refs](/react/docs/more-about-refs.html), you might notice that wrapping something into a higher-order component changes the ref to point to the wrapping component. In practice we discourage using refs for component communication so we don’t think it’s a big issue. In the future, we might consider adding [ref forwarding](https://github.com/facebook/react/issues/4213) to React to solve this annoyance.
### Rendering Logic
The next most common use case for mixins that we discovered in our codebase is sharing rendering logic between components.
Here is a typical example of this pattern:
```js
varRowMixin={
// Called by components from render()
renderHeader:function(){
return(
<divclassName='row-header'>
<h1>
{this.getHeaderText()/* Defined by components */}
</h1>
</div>
);
}
};
varUserRow=React.createClass({
mixins:[RowMixin],
// Called by RowMixin.renderHeader()
getHeaderText:function(){
returnthis.props.user.fullName;
},
render:function(){
return(
<div>
{this.renderHeader()/* Defined by RowMixin */}
<h2>{this.props.user.biography}</h2>
</div>
)
}
});
```
Multiple components may be sharing `RowMixin` to render the header, and each of them would need to define `getHeaderText()`.
#### Solution
If you see rendering logic inside a mixin, it’s time to extract a component!
Instead of `RowMixin`, we will define a `<RowHeader>` component. We will also replace the convention of defining a `getHeaderText()` method with the standard mechanism of top-data flow in React: passing props.
Finally, since neither of those components currently need lifecycle hooks or state, we can declare them as simple functions:
```js
functionRowHeader(props){
return(
<divclassName='row-header'>
<h1>{props.text}</h1>
</div>
);
}
functionUserRow(props){
return(
<div>
<RowHeadertext={props.user.fullName}/>
<h2>{props.user.biography}</h2>
</div>
);
}
```
Props keep component dependencies explicit, easy to replace, and enforceable with tools like [Flow](https://flowtype.org/) and [TypeScript](https://www.typescriptlang.org/).
> **Note:**
>
> Defining components as functions is not required. There is also nothing wrong with using lifecycle hooks and state—they are first-class React features. We use functional components in this example because they are easier to read and we didn’t need those extra features, but classes would work just as fine.
### Context
Another group of mixins we discovered were helpers for providing and consuming [React context](/react/docs/context.html). Context is an experimental unstable feature, has [certain issues](https://github.com/facebook/react/issues/2517), and will likely change its API in the future. We don’t recommend using it unless you’re confident there is no other way of solving your problem.
Nevertheless, if you already use context today, you might have been hiding its usage with mixins like this:
```js
varRouterMixin={
contextTypes:{
router:React.PropTypes.object.isRequired
},
// The mixin provides a method so that components
// don't have to use the context API directly.
push:function(path){
this.context.router.push(path)
}
};
varLink=React.createClass({
mixins:[RouterMixin],
handleClick:function(e){
e.stopPropagation();
// This method is defined in RouterMixin.
this.push(this.props.to);
},
render:function(){
return(
<aonClick={this.handleClick}>
{this.props.children}
</a>
);
}
});
module.exports=Link;
```
#### Solution
We agree that hiding context usage from consuming components is a good idea until the context API stabilizes. However, we recommend using higher-order components instead of mixins for this.
Let the wrapping component grab something from the context, and pass it down with props to the wrapped component:
```js
functionwithRouter(WrappedComponent){
returnReact.createClass({
contextTypes:{
router:React.PropTypes.object.isRequired
},
render:function(){
// The wrapper component reads something from the context
// and passes it down as a prop to the wrapped component.
// The wrapped component uses props instead of context.
this.props.router.push(this.props.to);
},
render:function(){
return(
<aonClick={this.handleClick}>
{this.props.children}
</a>
);
}
});
// Don't forget to wrap the component!
module.exports=withRouter(Link);
```
If you’re using a third party library that only provides a mixin, we encourage you to file an issue with them linking to this post so that they can provide a higher-order component instead. In the meantime, you can create a higher-order component around it yourself in exactly the same way.
### Utility Methods
Sometimes, mixins are used solely to share utility functions between components:
Sometimes people use mixins to selectively add logging to lifecycle hooks in some components. In the future, we intend to provide an [official DevTools API](https://github.com/facebook/react/issues/5306) that would let you implement something similar without touching the components. However it’s still very much a work in progress. If you heavily depend on logging mixins for debugging, you might want to keep using those mixins for a little longer.
If you can’t accomplish something with a component, a higher-order component, or a utility module, it could be mean that React should provide this out of the box. [File an issue](https://github.com/facebook/react/issues/new) to tell us about your use case for mixins, and we’ll help you consider alternatives or perhaps implement your feature request.
Mixins are not deprecated in the traditional sense. You can keep using them with `React.createClass()`, as we won’t be changing it further. Eventually, as ES6 classes gain more adoption and their usability problems in React are solved, we might split `React.createClass()` into a separate package because most people wouldn’t need it. Even in that case, your old mixins would keep working.
We believe that the alternatives above are better for the vast majority of cases, and we invite you to try writing React apps without using mixins.
**[Create React App](https://github.com/facebookincubator/create-react-app)** is a new officially supported way to create single-page React applications. It offers a modern build setup with no configuration.
## Getting Started
### Installation
First, install the global package:
```sh
npm install -g create-react-app
```
Node.js 4.x or higher is required.
### Creating an App
Now you can use it to create a new app:
```sh
create-react-app hello-world
```
This will take a while as npm installs the transitive dependencies, but once it’s done, you will see a list of commands you can run in the created folder:
Create React App uses both Webpack and Babel under the hood.
The console output is tuned to be minimal to help you focus on the problems:
ESLint is also integrated so lint warnings are displayed right in the console:
We only picked a small subset of lint rules that often lead to bugs.
### Building for Production
To build an optimized bundle, run `npm run build`:
It is minified, correctly envified, and the assets include content hashes for caching.
### One Dependency
Your `package.json` contains only a single build dependency and a few scripts:
```js
{
"name":"hello-world",
"dependencies":{
"react":"^15.2.1",
"react-dom":"^15.2.1"
},
"devDependencies":{
"react-scripts":"0.1.0"
},
"scripts":{
"start":"react-scripts start",
"build":"react-scripts build",
"eject":"react-scripts eject"
}
}
```
We take care of updating Babel, ESLint, and Webpack to stable compatible versions so you can update a single dependency to get them all.
### Zero Configuration
It is worth repeating: there are no configuration files or complicated folder structures. The tool only generates the files you need to build your app.
```
hello-world/
README.md
index.html
favicon.ico
node_modules/
package.json
src/
App.css
App.js
index.css
index.js
logo.svg
```
All the build settings are preconfigured and can’t be changed. Some features, such as testing, are currently missing. This is an intentional limitation, and we recognize it might not work for everybody. And this brings us to the last point.
### No Lock-In
We first saw this feature in [Enclave](https://github.com/eanplatter/enclave), and we loved it. We talked to [Ean](https://twitter.com/EanPlatter), and he was excited to collaborate with us. He already sent a few pull requests!
“Ejecting” lets you leave the comfort of Create React App setup at any time. You run a single command, and all the build dependencies, configs, and scripts are moved right into your project. At this point you can customize everything you want, but effectively you are forking our configuration and going your own way. If you’re experienced with build tooling and prefer to fine-tune everything to your taste, this lets you use Create React App as a boilerplate generator.
We expect that at early stages, many people will “eject” for one reason or another, but as we learn from them, we will make the default setup more and more compelling while still providing no configuration.
## Try It Out!
You can find [**Create React App**](https://github.com/facebookincubator/create-react-app) with additional instructions on GitHub.
This is an experiment, and only time will tell if it becomes a popular way of creating and building React apps, or fades into obscurity.
We welcome you to participate in this experiment. Help us build the React tooling that more people can use. We are always [open to feedback](https://github.com/facebookincubator/create-react-app/issues/11).
## The Backstory
React was one of the first libraries to embrace transpiling JavaScript. As a result, even though you can [learn React without any tooling](https://github.com/facebook/react/blob/3fd582643ef3d222a00a0c756292c15b88f9f83c/examples/basic-jsx/index.html), the React ecosystem has commonly become associated with an overwhelming explosion of tools.
Eric Clemmons called this phenomenon the “[JavaScript Fatigue](https://medium.com/@ericclemmons/javascript-fatigue-48d4011b6fc4)”:
>Ultimately, the problem is that by choosing React (and inherently JSX), you’ve unwittingly opted into a confusing nest of build tools, boilerplate, linters, & time-sinks to deal with before you ever get to create anything.
It is tempting to write code in ES2015 and JSX. It is sensible to use a bundler to keep the codebase modular, and a linter to catch the common mistakes. It is nice to have a development server with fast rebuilds, and a command to produce optimized bundles for production.
Combining these tools requires some experience with each of them. Even so, it is far too easy to get dragged into fighting small incompatibilities, unsatisfied peerDependencies, and illegible configuration files.
Many of those tools are plugin platforms and don’t directly acknowledge each other’s existence. They leave it up to the users to wire them together. The tools mature and change independently, and tutorials quickly get out of date.
<blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">Marc was almost ready to implement his "hello world" React app <a href="https://t.co/ptdg4yteF1">pic.twitter.com/ptdg4yteF1</a></p>— Thomas Fuchs (@thomasfuchs) <a href="https://twitter.com/thomasfuchs/status/708675139253174273">March 12, 2016</a></blockquote>
This doesn’t mean those tools aren’t great. To many of us, they have become indispensable, and we very much appreciate the effort of their maintainers. They already have too much on their plates to worry about the state of the React ecosystem.
Still, we knew it was frustrating to spend days setting up a project when all you wanted was to learn React. We wanted to fix this.
## Could We Fix This?
We found ourselves in an unusual dilemma.
So far, [our strategy](/react/contributing/design-principles.html#dogfooding) has been to only release the code that we are using at Facebook. This helped us ensure that every project is battle-tested and has clearly defined scope and priorities.
However, tooling at Facebook is different than at many smaller companies. Linting, transpilation, and packaging are all handled by powerful remote development servers, and product engineers don’t need to configure them. While we wish we could give a dedicated server to every user of React, even Facebook cannot scale that well!
The React community is very important to us. We knew that we couldn’t fix the problem within the limits of our open source philosophy. This is why we decided to make an exception, and to ship something that we didn’t use ourselves, but that we thought would be useful to the community.
## The Quest for a React <abbr title="Command Line Interface">CLI</abbr>
Having just attended [EmberCamp](http://embercamp.com/) a week ago, I was excited about [Ember CLI](https://ember-cli.com/). Ember users have a great “getting started” experience thanks to a curated set of tools united under a single command-line interface. I have heard similar feedback about [Elm Reactor](https://github.com/elm-lang/elm-reactor).
Providing a cohesive curated experience is valuable by itself, even if the user could in theory assemble those parts themselves. Kathy Sierra [explains it best](http://seriouspony.com/blog/2013/7/24/your-app-makes-me-fat):
>If your UX asks the user to make *choices*, for example, even if those choices are both clear and useful, the act of *deciding* is a cognitive drain. And not just *while* they’re deciding... even *after* we choose, an unconscious cognitive background thread is slowly consuming/leaking resources, “Was *that* the right choice?”
I never tried to write a command-line tool for React apps, and neither has [Christopher](https://twitter.com/vjeux). We were chatting on Messenger about this idea, and we decided to work together on it for a week as a hackathon project.
We knew that such projects traditionally haven’t been very successful in the React ecosystem. Christopher told me that multiple “React CLI” projects have started and failed at Facebook. The community tools with similar goals also exist, but so far they have not yet gained enough traction.
Still, we decided it was worth another shot. Christopher and I created a very rough proof of concept on the weekend, and [Kevin](https://twitter.com/lacker) soon joined us.
We invited some of the community members to collaborate with us, and we have spent this week working on this tool. We hope that you’ll enjoy using it! [Let us know what you think.](https://github.com/facebookincubator/create-react-app/issues/11)
We would like to express our gratitude to [Max Stoiber](https://twitter.com/mxstbr), [Jonny Buchanan](https://twitter.com/jbscript), [Ean Platter](https://twitter.com/eanplatter), [Tyler McGinnis](https://github.com/tylermcginnis), [Kent C. Dodds](https://github.com/kentcdodds), and [Eric Clemmons](https://twitter.com/ericclemmons) for their early feedback, ideas, and contributions.
This month marks a year since we released Relay and we'd like to share an update on the project and what's next.
## A Year In Review
A year after launch, we're incredibly excited to see an active community forming around Relay and that companies such as Twitter are [using Relay in production](https://fabric.io/blog/building-fabric-mission-control-with-graphql-and-relay):
> For a project like mission control, GraphQL and Relay were a near-perfect solution, and the cost of building it any other way justified the investment.
>
> -- <cite>Fin Hopkins</cite>
This kind of positive feedback is really encouraging (I'll admit to re-reading that post far too many times), and great motivation for us to keep going and make Relay even better.
With the community's help we've already come a long way since the technical preview. Here are some highlights:
- In March we added support for server-side rendering and for creating multiple instances of Relay on a single page. This was a coordinated effort over the course of several months by community members [Denis Nedelyaev](https://github.com/denvned) and [Gerald Monaco](https://github.com/devknoll) (now at Facebook).
- Also in March we added support for React Native. While we use Relay and React Native together internally, they didn't quite work together in open-source out of the box. We owe a big thanks to [Adam Miskiewicz](https://github.com/skevy), [Tom Burns](https://github.com/boourns), [Gaëtan Renaudeau](https://github.com/gre), [David Aurelio](https://github.com/davidaurelio), [Martín Bigio](https://github.com/martinbigio), [Paul O’Shannessy](https://github.com/zpao), [Ben Alpert](https://github.com/spicyj), and many others who helped track down and resolve issues. Finally, thanks to [Steven Luscher](https://github.com/steveluscher) for coordinating this effort and building the first Relay/ReactNative example app.
We've also seen some great open-source projects spring up around Relay:
- [Denis Nedelyaev](https://github.com/denvned) created [isomorphic-relay](https://github.com/denvned/isomorphic-relay/), a package that helps developers build server-rendered Relay apps where data is prepared on the server and then used to bootstrap the app on the client.
- [Jimmy Jia](https://github.com/taion) created [react-router-relay](https://github.com/relay-tools/react-router-relay) to integrate Relay data-fetching into React Router.
- [Pavel Chertorogov](https://github.com/nodkz) released [relay-network-layer](https://github.com/nodkz/react-relay-network-layer), which adds features such as batching query requests, middleware, authentication, logging, and more.
This is just a small sampling of the community's contributions. So far we've merged over 300 PRs - about 25% of our commits - from over 80 of you. These PRs have improved everything from the website and docs down the very core of the framework. We're humbled by these outstanding contributions and excited to keep working with each of you!
# Retrospective & Roadmap
Earlier this year we paused to reflect on the state of the project. What was working well? What could be improved? What features should we add, and what could we remove? A few themes emerged: performance on mobile, developer experience, and empowering the community.
## Mobile Perf
First, Relay was built to serve the needs of product developers at Facebook. In 2016, that means helping developers to build apps that work well on [mobile devices connecting on slower networks](https://newsroom.fb.com/news/2015/10/news-feed-fyi-building-for-all-connectivity/). For example, people in developing markets commonly use [2011 year-class phones](https://code.facebook.com/posts/307478339448736/year-class-a-classification-system-for-android/) and connect via [2G class networks](https://code.facebook.com/posts/952628711437136/classes-performance-and-network-segmentation-on-android/). These scenarios present their own challenges.
Therefore, one of our primary goals this year is to optimize Relay for performance on low-end mobile devices *first*, knowing that this can translate to improved performance on high-end devices as well. In addition to standard approaches such as benchmarking, profiling, and optimizations, we're also working on big-picture changes.
For example, in today's Relay, here's what happens when an app is opened. First, React Native starts initializing the JavaScript context (loading and parsing your code and then running it). When this finishes, the app executes and Relay sees that you need data. It constructs and prints the query, uploads the query text to the server, processes the response, and renders your app. (Note that this process applies on the web, except that the code has to be *downloaded* instead of loaded from the device.)
Ideally, though, we could begin fetching data as soon as the native code had loaded - in parallel with the JS context initialization. By the time your JS code was ready to run, the data-fetching would already be under way. To do this we would need a way to determine *statically* - at build time - what query an application would send.
The key is that GraphQL is already static - we just need to fully embrace this fact. More on this later.
## Developer Experience
Next, we've paid attention to the community's feedback and know that, to put it simply, Relay could be "easier" to use (and "simpler" too). This isn't entirely surprising to us - Relay was originally designed as a routing library and gradually morphed into a data-fetching library. Concepts like Relay "routes", for example, no longer serve as critical a role and are just one more concept that developers have to learn about. Another example is mutations: while writes *are* inherently more complex than reads, our API doesn't make the simple things simple enough.
Alongside our focus on mobile performance, we've also kept the developer experience in mind as we evolve Relay core.
## Empowering the Community
Finally, we want to make it easier for people in the community to develop useful libraries that work with Relay. By comparison, React's small surface area - components - allows developers to build cool things like routing, higher-order components, or reusable text editors. For Relay, this would mean having the framework provide core primitives that users can build upon. We want it to be possible for the community to integrate Relay with view libraries other than React, or to build real-time subscriptions as a complementary library.
# What's Next
These were big goals, and also a bit scary; we knew that incremental improvements would only allow us to move so fast. So in April we started a project to build a new implementation of Relay core targeting low-end mobile devices from the start.
As you can guess since we're writing this, the experiment was a success. The result is a new core that retains the best parts of Relay today - colocated components & data-dependencies, automatic data/view consistency, declarative data-fetching - while improving performance on mobile devices and addressing several common areas of confusion.
We're currently focused on shipping the first applications using the new core: ironing out bugs, refining the API changes and developer experience, and adding any missing features. We're excited to bring these changes to open source, and will do so once we've proven them in production. We'll go into more detail in some upcoming talks - links below - but for now here's an overview:
- **Static Queries**: By adding a couple of Relay-specific directives, we've been able to retain the expressivity of current Relay queries using static syntax (concretely: you know what query an app will execute just by looking at the source text, without having to run that code). For starters this will allow Relay apps to start fetching data in parallel with JavaScript initialization. But it also unlocks other possibilities: knowing the query ahead of time means that we can generate optimized code for handling query responses, for example, or for reading query data from an offline cache.
- **Expressive Mutations**: We'll continue to support a higher-level mutation API for common cases, but will also provide a lower-level API that allows "raw" data access where necessary. If you need to order a list of cached elements, for example, there will be a way to `sort()` it.
- **Route-less Relay**: Routes will be gone in open source. Instead of a route with multiple query definitions, you'll just provide a single query with as many root fields as you want.
- **Cache Eviction/Garbage Collection**: The API and architecture is designed from the start to allow removing cached data that is no longer referenced by a mounted view.
Stepping back, we recognize that any API changes will require an investment on your part. To make the transition easier, though, *we will continue to support the current API for the foreseeable future* (we're still using it too). And as much as possible we will open-source the tools that we use to migrate our own code. Ideas that we're exploring include codemods, an interoperability layer for the old/new APIs, and tutorials & guides to ease migration.
Ultimately, we're making these changes because we believe they make Relay better all around: simpler for developers building apps and faster for the people using them.
# Conclusion
If you made it this far, congrats and thanks for reading! We'll be sharing more information about these changes in some upcoming talks:
- [Greg Hurrell](https://github.com/wincent) will presenting a Relay "Deep Dive" at the [Silicon Valley ReactJS Meetup](http://www.meetup.com/Silicon-Valley-ReactJS-Meetup/events/232236845/) on August 17th.
- I ([@josephsavona](https://github.com/josephsavona)) will be speaking about Relay at [React Rally](http://www.reactrally.com) on August 25th.
We can't wait to share the new code with you and are working as fast as we can to do so!
Just three and a half years ago we open sourced a little JavaScript library called React. The journey since that day has been incredibly exciting.
## Commemorative T-Shirt
In order to celebrate 50,000 GitHub stars, [Maggie Appleton](http://www.maggieappleton.com/) from [egghead.io](http://egghead.io/) has designed us a special T-shirt, which will be available for purchase from Teespring **only for a week** through Thursday, October 6. Maggie also wrote [a blog post](https://www.behance.net/gallery/43269677/Reacts-50000-Stars-Shirt) showing all the different concepts she came up with before settling on the final design.
Proceeds from the shirts will be donated to [CODE2040](http://www.code2040.org/), a nonprofit that creates access, awareness, and opportunities in technology for underrepresented minorities with a specific focus on Black and Latinx talent.
## Archeology
We've spent a lot of time trying to explain the concepts behind React and the problems it attempts to solve, but we haven't talked much about how React evolved before being open sourced. This milestone seemed like as good a time as any to dig through the earliest commits and share some of the more important moments and fun facts.
The story begins in our ads org, where we were building incredibly sophisticated client side web apps using an internal MVC framework called [BoltJS](http://web.archive.org/web/20130608154901/http://shaneosullivan.github.io/boltjs/intro.html). Here's a sample of what some Bolt code looked like:
```js
varCarView=require('javelin/core').createClass({
name:'CarView',
extend:require('container').Container,
properties:{
wheels:4,
},
declare:function(){
return{
childViews:[
{content:'I have '},
{ref:'wheelView'},
{content:' wheels'}
]
};
},
setWheels:function(wheels){
this.findRef('wheelView').setContent(wheels);
},
getWheels:function(){
returnthis.findRef('wheelView').getContent();
},
});
varcar=newCarView();
car.setWheels(3);
car.placeIn(document.body);
//<div>
// <div>I have </div>
// <div>3</div>
// <div> wheels</div>
//</div>
```
Bolt introduced a number of APIs and features that would eventually make their way into React including `render`, `createClass`, and `refs`. Bolt introduced the concept of `refs` as a way to create references to nodes that can be used imperatively. This was relevant for legacy interoperability and incremental adoption, and while React would eventually strive to be a lot more functional, `refs` proved to be a very useful way to break out of the functional paradigm when the need arose.
But as our applications grew more and more sophisticated, our Bolt codebases got pretty complicated. Recognizing some of the framework's shortcomings, [Jordan Walke](https://twitter.com/jordwalke) started experimenting with a side-project called [FaxJS](https://github.com/jordwalke/FaxJs). His goal was to solve many of the same problems as Bolt, but in a very different way. This is actually where most of React's fundamentals were born, including props, state, re-evaluating large portions of the tree to “diff” the UI, server-side rendering, and a basic concept of components.
```js
TestProject.PersonDisplayer={
structure:function(){
returnDiv({
classSet:{personDisplayerContainer:true},
titleDiv:Div({
classSet:{personNameTitle:true},
content:this.props.name
}),
nestedAgeDiv:Div({
content:'Interests: '+this.props.interests
})
});
}
};
```
## FBolt is Born
Through his FaxJS experiment, Jordan became convinced that functional APIs — which discouraged mutation — offered a better, more scalable way to build user interfaces. He imported his library into Facebook's codebase in March of 2012 and renamed it “FBolt”, signifying an extension of Bolt where components are written in a functional programming style. Or maybe “FBolt” was a nod to FaxJS – he didn't tell us! ;)
The interoperability between FBolt and Bolt allowed us to experiment with replacing just one component at a time with more functional component APIs. We could test the waters of this new functional paradigm, without having to go all in. We started with the components that were clearly best expressed functionally and then we would later continue to push the boundaries of what we could express as functions.
Realizing that FBolt wouldn't be a great name for the library when used on its own, Jordan Walke and [Tom Occhino](https://twitter.com/tomocchino) decided on a new name: “React.” After Tom sent out the diff to rename everything to React, Jordan commented:
> Jordan Walke:
I might add for the sake of discussion, that many systems advertise some kind of reactivity, but they usually require that you set up some kind of point-to-point listeners and won't work on structured data. This API reacts to any state or property changes, and works with data of any form (as deeply structured as the graph itself) so I think the name is fitting.
Most of Tom's other commits at the time were on the first version of [GraphiQL](https://github.com/graphql/graphiql), a project which was recently open sourced.
## Adding JSX
Since about 2010 Facebook has been using an extension of PHP called [XHP](https://www.facebook.com/notes/facebook-engineering/xhp-a-new-way-to-write-php/294003943919/), which enables engineers to create UIs using XML literals right inside their PHP code. It was first introduced to help prevent XSS holes but ended up being an excellent way to structure applications with custom components.
```js
finalclass:a:postextends:x:element{
attribute:a;
protectedfunctionrender():XHPRoot{
$anchor=<a>{$this->getChildren()}</a>;
$form=(
<form
method="post"
action={$this->:href}
target={$this->:target}
class="postLink"
>{$anchor}</form>
);
$this->transferAllAttributes($anchor);
return$form;
}
}
```
Before Jordan's work had even made its way into the Facebook codebase, Adam Hupp implemented an XHP-like concept for JavaScript, written in Haskell. This system enabled you to write the following inside a JavaScript file:
```js
function:example:hello(attrib,children){
return(
<divclass="special">
<h1>Hello,World!</h1>
{children}
</div>
);
}
```
It would compile the above into the following normal ES3-compatible JavaScript:
```js
functionjsx_example_hello(attrib,children){
return(
S.create("div",{"class":"special"},[
S.create("h1",{},["Hello, World!"]),
children
]
);
}
```
In this prototype, `S.create` would immediately create and return a DOM node. Most of the conversations on this prototype revolved around the performance characteristics of `innerHTML` versus creating DOM nodes directly. At the time, it would have been less than ideal to push developers universally in the direction of creating DOM nodes directly since it did not perform as well, especially in Firefox and IE. Facebook's then-CTO [Bret Taylor](https://twitter.com/btaylor) chimed in on the discussion at the time in favor of `innerHTML` over `document.createElement`:
> Bret Taylor:
If you are not convinced about innerHTML, here is a small microbenchmark. It is about the same in Chrome. innerHTML is about 30% faster in the latest version of Firefox (much more in previous versions), and about 90% faster in IE8.
This work was eventually abandoned but was revived after React made its way into the codebase. Jordan sidelined the previous performance discussions by introducing the concept of a “Virtual DOM,” though its eventual name didn't exist yet.
> Jordan Walke:
> For the first step, I propose that we do the easiest, yet most general transformation possible. My suggestion is to simply map xml expressions to function call expressions.
> At this point, JSX doesn't need to know about React - it's just a convenient way to write function calls. Coincidentally, React's primary abstraction is the function. Okay maybe it's not so coincidental ;)
Adam made a very insightful comment, which is now the default way we write lists in React with JSX.
> Adam Hupp:
> I think we should just treat arrays of elements as a frag. This is useful for constructs like:
> In this case the ul(..) will get a childList with a single child, which is itself a list.
React didn't end up using Adam's implementation directly. Instead, we created JSX by forking [js-xml-literal](https://github.com/laverdet/js-xml-literal), a side project by XHP creator Marcel Laverdet. JSX took its name from js-xml-literal, which Jordan modified to just be syntactic sugar for deeply nested function calls.
## API Churn
During the first year of React, internal adoption was growing quickly but there was quite a lot of churn in the component APIs and naming conventions:
* `project` was renamed to `declare` then to `structure` and finally to `render`.
* `Componentize` was renamed to `createComponent` and finally to `createClass`.
As the project was about to be open sourced, [Lee Byron](https://twitter.com/leeb) sat down with Jordan Walke, Tom Occhino and Sebastian Markbåge in order to refactor, reimplement, and rename one of React's most beloved features – the lifecycle API. Lee [came up with a well-designed API](https://gist.github.com/vjeux/f2b015d230cc1ab18ed1df30550495ed) that is still in place today.
* Concepts
* component - a ReactComponent instance
* state - internal state to a component
* props - external state to a component
* markup - the stringy HTML-ish stuff components generate
* DOM - the document and elements within the document
* Actions
* mount - to put a component into a DOM
* initialize - to prepare a component for rendering
* update - a transition of state (and props) resulting a render.
* render - a side-effect-free process to get the representation (markup) of a component.
* validate - make assertions about something created and provided
* destroy - opposite of initialize
* Operands
* create - make a new thing
* get - get an existing thing
* set - merge into existing
* replace - replace existing
* receive - respond to new data
* force - skip checks to do action
* Notifications
* shouldObjectAction
* objectWillAction
* objectDidAction
## Instagram
In 2012, Instagram got acquired by Facebook. [Pete Hunt](https://twitter.com/floydophone), who was working on Facebook photos and videos at the time, joined their newly formed web team. He wanted to build their website completely in React, which was in stark contrast with the incremental adoption model that had been used at Facebook.
To make this happen, React had to be decoupled from Facebook's infrastructure, since Instagram didn't use any of it. This project acted as a forcing function to do the work needed to open source React. In the process, Pete also discovered and promoted a little project called Webpack. He also implemented the `renderToString` primitive which was needed to do server-side rendering.
As we started to prepare for the open source launch, [Maykel Loomans](https://twitter.com/miekd), a designer on Instagram, made a mock of what the website could look like. The header ended up defining the visual identity of React: its logo and the electric blue color!
In its earliest days, React benefited tremendously from feedback, ideas, and technical contributions of early adopters and collaborators all over the company. While it might look like an overnight success in hindsight, the story of React is actually a great example of how new ideas often need to go through several rounds of refinement, iteration, and course correction over a long period of time before reaching their full potential.
React's approach to building user interfaces with functional programming principles has changed the way we do things in just a few short years. It goes without saying, but React would be nothing without the amazing open source community that's built up around it!
We didn't announce the [previous](https://github.com/facebook/react/blob/master/CHANGELOG.md#1510-may-20-2016) [minor](https://github.com/facebook/react/blob/master/CHANGELOG.md#1520-july-1-2016) [releases](https://github.com/facebook/react/blob/master/CHANGELOG.md#1530-july-29-2016) on the blog because most of the changes were bug fixes. However, 15.4.0 is a special release, and we would like to highlight a few notable changes in it.
### Separating React and React DOM
[More than a year ago](/react/blog/2015/09/10/react-v0.14-rc1.html#two-packages-react-and-react-dom), we started separating React and React DOM into separate packages. We deprecated `React.render()` in favor of `ReactDOM.render()` in React 0.14, and removed DOM-specific APIs from `React` completely in React 15. However, the React DOM implementation still [secretly lived inside the React package](https://www.reddit.com/r/javascript/comments/3m6wyu/found_this_line_in_the_react_codebase_made_me/cvcyo4a/).
In React 15.4.0, we are finally moving React DOM implementation to the React DOM package. The React package will now contain only the renderer-agnostic code such as `React.Component` and `React.createElement()`.
This solves a few long-standing issues, such as [errors](https://github.com/facebook/react/issues/7386) when you import React DOM in the same file as the [snapshot testing](https://facebook.github.io/jest/blog/2016/07/27/jest-14.html) renderer.
**If you only use the official and documented React APIs you won't need to change anything in your application.**
However, there is a possibility that you imported private APIs from `react/lib/*`, or that a package you rely on might use them. We would like to remind you that this was never supported, and that your apps should not rely on internal APIs. The React internals will keep changing as we work to make React better.
Another thing to watch out for is that React DOM Server is now about the same size as React DOM since it contains its own copy of the React reconciler. We don't recommend using React DOM Server on the client in most cases.
### Profiling Components with Chrome Timeline
You can now visualize React components in the Chrome Timeline. This lets you see which components exactly get mounted, updated, and unmounted, how much time they take relative to each other.
<center><img src="/react/img/blog/react-perf-chrome-timeline.png" width="651" height="228" alt="React components in Chrome timeline" /></center>
To use it:
1. Load your app with `?react_perf` in the query string (for example, `http://localhost:3000/?react_perf`).
2. Open the Chrome DevTools **Timeline** tab and press **Record**.
3. Perform the actions you want to profile. Don't record more than 20 seconds or Chrome might hang.
4. Stop recording.
5. React events will be grouped under the **User Timing** label.
Note that the numbers are relative so components will render faster in production. Still, this should help you realize when unrelated UI gets updated by mistake, and how deep and how often your UI updates occur.
Currently Chrome, Edge, and IE are the only browsers supporting this feature, but we use the standard [User Timing API](https://developer.mozilla.org/en-US/docs/Web/API/User_Timing_API) so we expect more browsers to add support for it.
### Mocking Refs for Snapshot Testing
If you're using Jest [snapshot testing](https://facebook.github.io/jest/blog/2016/07/27/jest-14.html), you might have had [issues](https://github.com/facebook/react/issues/7371) with components that rely on refs. With React 15.4.0, we introduce a way to provide mock refs to the test renderer. For example, consider this component using a ref in `componentDidMount`:
```js{5,11}
import React from 'react';
export default class MyInput extends React.Component {
componentDidMount() {
this.input.focus();
}
render() {
return (
<input
ref={node => this.input = node}
/>
);
}
}
```
With snapshot renderer, `this.input` will be `null` because there is no DOM. React 15.4.0 lets us avoid such crashes by passing a custom `createNodeMock` function to the snapshot renderer in an `options` argument:
```js{5-12,16}
import React from 'react';
import MyInput from './MyInput';
import renderer from 'react-test-renderer';
function createNodeMock(element) {
if (element.type === 'input') {
return {
focus() {},
};
}
return null;
}
it('renders correctly', () => {
const options = {createNodeMock};
const tree = renderer.create(<MyInput />, options);
expect(tree).toMatchSnapshot();
});
```
We would like to thank [Brandon Dail](https://github.com/Aweary) for implementing this feature.
You can learn more about snapshot testing in [this Jest blog post](https://facebook.github.io/jest/blog/2016/07/27/jest-14.html).
---
## Installation
We recommend using [Yarn](https://yarnpkg.com/) or [npm](https://www.npmjs.com/) for managing front-end dependencies. If you're new to package managers, the [Yarn documentation](https://yarnpkg.com/en/docs/getting-started) is a good place to get started.
To install React with Yarn, run:
```bash
yarn add react@15.4.0 react-dom@15.4.0
```
To install React with npm, run:
```bash
npm install --save react@15.4.0 react-dom@15.4.0
```
We recommend using a bundler like [webpack](https://webpack.js.org/) or [Browserify](http://browserify.org/) so you can write modular code and bundle it together into small packages to optimize load time.
Remember that by default, React runs extra checks and provides helpful warnings in development mode. When deploying your app, make sure to [compile it in production mode](/react/docs/installation.html#development-and-production-versions).
In case you don't use a bundler, we also provide pre-built bundles in the npm packages which you can [include as script tags](/react/docs/installation.html#using-a-cdn) on your page:
* **React**
Dev build with warnings: [react/dist/react.js](https://unpkg.com/react@15.4.0/dist/react.js)
Minified build for production: [react/dist/react.min.js](https://unpkg.com/react@15.4.0/dist/react.min.js)
* **React with Add-Ons**
Dev build with warnings: [react/dist/react-with-addons.js](https://unpkg.com/react@15.4.0/dist/react-with-addons.js)
Minified build for production: [react/dist/react-with-addons.min.js](https://unpkg.com/react@15.4.0/dist/react-with-addons.min.js)
* **React DOM** (include React in the page before React DOM)
Dev build with warnings: [react-dom/dist/react-dom.js](https://unpkg.com/react-dom@15.4.0/dist/react-dom.js)
Minified build for production: [react-dom/dist/react-dom.min.js](https://unpkg.com/react-dom@15.4.0/dist/react-dom.min.js)
* **React DOM Server** (include React in the page before React DOM Server)
Dev build with warnings: [react-dom/dist/react-dom-server.js](https://unpkg.com/react-dom@15.4.0/dist/react-dom-server.js)
Minified build for production: [react-dom/dist/react-dom-server.min.js](https://unpkg.com/react-dom@15.4.0/dist/react-dom-server.min.js)
We've also published version `15.4.0` of the `react`, `react-dom`, and addons packages on npm and the `react` package on bower.
- - -
## Changelog
### React
* React package and browser build no longer "secretly" includes React DOM.
<small>([@sebmarkbage](https://github.com/sebmarkbage) in [#7164](https://github.com/facebook/react/pull/7164) and [#7168](https://github.com/facebook/react/pull/7168))</small>
* Required PropTypes now fail with specific messages for null and undefined.
<small>([@chenglou](https://github.com/chenglou) in [#7291](https://github.com/facebook/react/pull/7291))</small>
* Improved development performance by freezing children instead of copying.
<small>([@keyanzhang](https://github.com/keyanzhang) in [#7455](https://github.com/facebook/react/pull/7455))</small>
### React DOM
* Fixed occasional test failures when React DOM is used together with shallow renderer.
<small>([@goatslacker](https://github.com/goatslacker) in [#8097](https://github.com/facebook/react/pull/8097))</small>
* Added a warning for invalid `aria-` attributes.
<small>([@jessebeach](https://github.com/jessebeach) in [#7744](https://github.com/facebook/react/pull/7744))</small>
* Added a warning for using `autofocus` rather than `autoFocus`.
<small>([@hkal](https://github.com/hkal) in [#7694](https://github.com/facebook/react/pull/7694))</small>
* Removed an unnecessary warning about polyfilling `String.prototype.split`.
<small>([@nhunzaker](https://github.com/nhunzaker) in [#7629](https://github.com/facebook/react/pull/7629))</small>
* Clarified the warning about not calling PropTypes manually.
<small>([@jedwards1211](https://github.com/jedwards1211) in [#7777](https://github.com/facebook/react/pull/7777))</small>
* The unstable `batchedUpdates` API now passes the wrapped function's return value through.
<small>([@bgnorlov](https://github.com/bgnorlov) in [#7444](https://github.com/facebook/react/pull/7444))</small>
* Fixed a bug with updating text in IE 8.
<small>([@mnpenner](https://github.com/mnpenner) in [#7832](https://github.com/facebook/react/pull/7832))</small>
### React Perf
* When ReactPerf is started, you can now view the relative time spent in components as a chart in Chrome Timeline.
<small>([@gaearon](https://github.com/gaearon) in [#7549](https://github.com/facebook/react/pull/7549))</small>
### React Test Utils
* If you call `Simulate.click()` on a `<input disabled onClick={foo} />` then `foo` will get called whereas it didn't before.
<small>([@nhunzaker](https://github.com/nhunzaker) in [#7642](https://github.com/facebook/react/pull/7642))</small>
### React Test Renderer
* Due to packaging changes, it no longer crashes when imported together with React DOM in the same file.
<small>([@sebmarkbage](https://github.com/sebmarkbage) in [#7164](https://github.com/facebook/react/pull/7164) and [#7168](https://github.com/facebook/react/pull/7168))</small>
* `ReactTestRenderer.create()` now accepts `{createNodeMock: element => mock}` as an optional argument so you can mock refs with snapshot testing.
<small>([@Aweary](https://github.com/Aweary) in [#7649](https://github.com/facebook/react/pull/7649) and [#8261](https://github.com/facebook/react/pull/8261))</small>
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