cb1ff430e8
* Move DEV-only function right above where it's used I don't like looking at this top-level function #petty * Use different dispatchers for functions & classes Classes support readContext, but not any of the other dispatcher methods. Function support all methods. This is a more robust version of our previous strategy of checking whether `currentlyRenderingFiber` is null. As a next step, we can use a separate dispatcher for each phase of the render cycle (mount versus update). * Use separate dispatchers for mount and update * Remove mount code from update path Deletes mount-specific code from the update path, since it should be unreachable. To continue supporting progressive enhancement (mounting new hooks at the end of the list), we detect when there are no more current hooks and switch back to the mount dispatcher. Progressive enhancement isn't officially supported yet, so it will continue to warn. * Factoring nits * Fix Flow Had to cheat more than I would like * More Flow nits * Switch back to using a special dispatcher for nested hooks in DEV In order for this strategy to work, I had to revert progressive enhancement support (appending hooks to the end). It was previously a warning but now it results in an error. We'll reconsider later. * Always pass args to updateState and updateReducer Even though the extra args are only used on mount, to ensure type consistency.
react-test-renderer
This package provides an experimental React renderer that can be used to render React components to pure JavaScript objects, without depending on the DOM or a native mobile environment.
Essentially, this package makes it easy to grab a snapshot of the "DOM tree" rendered by a React DOM or React Native component without using a browser or jsdom.
Documentation:
https://reactjs.org/docs/test-renderer.html
Usage:
const ReactTestRenderer = require('react-test-renderer');
const renderer = ReactTestRenderer.create(
<Link page="https://www.facebook.com/">Facebook</Link>
);
console.log(renderer.toJSON());
// { type: 'a',
// props: { href: 'https://www.facebook.com/' },
// children: [ 'Facebook' ] }
You can also use Jest's snapshot testing feature to automatically save a copy of the JSON tree to a file and check in your tests that it hasn't changed: https://facebook.github.io/jest/blog/2016/07/27/jest-14.html.