Files
react-native/Libraries/Performance/PureComponentDebug.js
James Ide 0ee5f68929 Migrate "Libraries" from Haste to standard path-based requires (sans vendor & renderers) (#24749)
Summary:
This is the next step in moving RN towards standard path-based requires. All the requires in `Libraries` have been rewritten to use relative requires with a few exceptions, namely, `vendor` and `Renderer/oss` since those need to be changed upstream. This commit uses relative requires instead of `react-native/...` so that if Facebook were to stop syncing out certain folders and therefore remove code from the react-native package, internal code at Facebook would not need to change.

See the umbrella issue at https://github.com/facebook/react-native/issues/24316 for more detail.

[General] [Changed] - Migrate "Libraries" from Haste to standard path-based requires
Pull Request resolved: https://github.com/facebook/react-native/pull/24749

Differential Revision: D15258017

Pulled By: cpojer

fbshipit-source-id: a1f480ea36c05c659b6f37c8f02f6f9216d5a323
2019-05-08 08:48:59 -07:00

74 lines
2.2 KiB
JavaScript

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
* @format
*/
'use strict';
const React = require('react');
opaque type DoNotCommitUsageOfPureComponentDebug = {};
/**
* Identifies which prop or state changes triggered a re-render of a PureComponent. Usage:
*
* Change `extends React.PureComponent` to `extends PureComponentDebug` or inject it
* everywhere by putting this line in your app setup:
*
* React.PureComponent = require('PureComponentDebug');
*
* Should only be used for local testing, and will trigger a flow failure if you try to
* commit any usages.
*/
class PureComponentDebug<
P: DoNotCommitUsageOfPureComponentDebug,
S: ?Object = void,
> extends React.Component<P, S> {
shouldComponentUpdate(nextProps: P, nextState: S): boolean {
const tag = this.constructor.name;
let ret = false;
const prevPropsKeys = Object.keys(this.props);
const nextPropsKeys = Object.keys(nextProps);
if (prevPropsKeys.length !== nextPropsKeys.length) {
ret = true;
console.warn(
'PureComponentDebug: different prop keys',
tag,
prevPropsKeys.filter(key => !nextPropsKeys.includes(key)),
nextPropsKeys.filter(key => !prevPropsKeys.includes(key)),
);
}
const prevStateKeys = Object.keys(this.state || {});
const nextStateKeys = Object.keys(nextState || {});
if (prevStateKeys.length !== nextStateKeys.length) {
ret = true;
console.warn(
'PureComponentDebug: different state keys',
tag,
prevStateKeys.filter(key => !nextStateKeys.includes(key)),
nextStateKeys.filter(key => !prevStateKeys.includes(key)),
);
}
for (const key in this.props) {
if (this.props[key] !== nextProps[key]) {
ret = true;
console.warn('PureComponentDebug: different prop values', tag, key);
}
}
for (const key in this.state) {
if (this.state[key] !== (nextState || {})[key]) {
ret = true;
console.warn('PureComponentDebug: different state values', tag, key);
}
}
return ret;
}
}
module.exports = PureComponentDebug;