3ea3274ca4
This is the first step towards descriptors. This will start cloning the component when it's mounted instead of mounting the first instance. This avoids an issue where a reference to the first instance can hang around in props. Since a mounted component gets mutated, the descriptor changes. We don't need to clone the props object itself. Mutating the shallow props object of a child that's passed into you is already flawed. Those cases need to use cloneWithProps. A props object is considered shallow frozen after it leaves the render it was created in.
62 lines
2.2 KiB
JavaScript
62 lines
2.2 KiB
JavaScript
/**
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* Copyright 2013-2014 Facebook, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* @providesModule shouldUpdateReactComponent
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* @typechecks static-only
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*/
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"use strict";
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/**
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* Given a `prevComponentInstance` and `nextComponent`, determines if
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* `prevComponentInstance` should be updated as opposed to being destroyed or
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* replaced by a new instance. The second argument is a descriptor. Future
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* versions of the reconciler should only compare descriptors to other
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* descriptors.
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*
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* @param {?object} prevComponentInstance
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* @param {?object} nextDescriptor
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* @return {boolean} True if `prevComponentInstance` should be updated.
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* @protected
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*/
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function shouldUpdateReactComponent(prevComponentInstance, nextDescriptor) {
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// TODO: Remove warning after a release.
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if (prevComponentInstance && nextDescriptor &&
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prevComponentInstance.constructor === nextDescriptor.constructor && (
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(prevComponentInstance.props && prevComponentInstance.props.key) ===
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(nextDescriptor.props && nextDescriptor.props.key)
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)) {
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if (prevComponentInstance._owner === nextDescriptor._owner) {
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return true;
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} else {
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if (__DEV__) {
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if (prevComponentInstance.state) {
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console.warn(
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'A recent change to React has been found to impact your code. ' +
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'A mounted component will now be unmounted and replaced by a ' +
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'component (of the same class) if their owners are different. ' +
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'Previously, ownership was not considered when updating.',
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prevComponentInstance,
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nextDescriptor
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);
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}
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}
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}
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}
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return false;
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}
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module.exports = shouldUpdateReactComponent;
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