Ben Alpert
de1dacdb28
Fixes #1392. Previously, ReactComponent.updateComponent set the new props and owner and updated the component's refs. Because it did the actual props assignment, it had to be called by ReactCompositeComponent between componentWillMount and componentDidMount, meaning that it was skipped if shouldComponentUpdate returned false. Now, updateComponent takes the old and new descriptors and only updates refs, allowing a subclass to call updateComponent at a convenient time (specifically, it can be before `this._descriptor` is updated if the subclass also overrides performUpdateIfNecessary). The new update cycle for composites is: - receiveComponent is called which stores `this._pendingDescriptor` and calls performUpdateIfNecessary directly or a state update is enqueued, in which case ReactUpdates will call performUpdateIfNecessary - performUpdateIfNecessary ensures that an update is still pending (which might no longer be the case if an update is queued for a subcomponent that was updated through a parent's reconciliation) and calls updateComponent with the old and new descriptors - updateComponent calls super to update refs, then calls componentWillReceiveProps (if applicable) and shouldComponentUpdate -- if shouldComponentUpdate returns false, `this._descriptor`, `this.props`, and `this.state` are updated and the update is skipped; else, _performComponentUpdate is called - _performComponentUpdate calls componentWillUpdate and _updateRenderedComponent, and enqueues the componentDidUpdate call (in that order) - _updateRenderedComponent calls render and updates the rendered component appropriately For DOM components (essentially unchanged): - receiveComponent is called which does a short-circuit check for descriptor equality and delegates to super (which stores `this._pendingDescriptor` and calls performUpdateIfNecessary) - performUpdateIfNecessary (not overridden) sets new values for `this.props`, etc. and calls updateComponent - updateComponent does the DOM property and children updates (some synchronously, some queued for the transaction close) For text and ART components (unchanged): - receiveComponent updates the DOM or ART directly based on the new props - updateComponent is never called Notable changes: - When shouldComponentUpdate returns false, refs are still updated - ReactDefaultPerf now includes lifecycle methods in component timings - updateComponent's signature changed (technically this is part of the public API, though we've never documented it) Test Plan: jest
React 
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 uses a virtual DOM diff implementation for ultra-high performance. It can also render on the server using Node.js — no heavy browser DOM required.
- Data flow: React implements one-way reactive data flow which reduces boilerplate and is easier to reason about than traditional data binding.
Learn how to use React in your own project.
Examples
We have several examples on the website. Here is the first one to get you started:
var HelloMessage = React.createClass({
render: function() {
return <div>Hello {this.props.name}</div>;
}
});
React.renderComponent(
<HelloMessage name="John" />,
document.getElementById('container')
);
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. 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.
Installation
The fastest way to get started is to serve JavaScript from the CDN (also available on CDNJS):
<!-- The core React library -->
<script src="http://fb.me/react-0.11.2.js"></script>
<!-- In-browser JSX transformer, remove when pre-compiling JSX. -->
<script src="http://fb.me/JSXTransformer-0.11.2.js"></script>
We've also built a starter kit 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.
If you'd like to use bower, it's as easy as:
bower install --save react
Contribute
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.
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
nodeinstalled at v0.10.0+ (it might work at lower versions, we just haven't tested). - You are familiar with
npmand know whether or not you need to usesudowhen installing packages globally. - You are familiar with
git.
Build
Once you have the repository cloned, building a copy of react.js is really easy.
# 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:
# Build and run tests with PhantomJS
grunt test
# Build and run tests in your browser
grunt test --debug
# For speed, you can use fasttest and add --filter to only run one test
grunt fasttest --filter=ReactIdentity
# Lint the code with JSHint
grunt lint
# Wipe out build directory
grunt clean
License
React is BSD licensed. We also provide an additional patent grant.
React documentation is Creative Commons licensed.
Examples provided in this repository and in the documentation are separately licensed.
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.