Sebastian Markbage
d0719a5ea4
This copies the propType and contextType validation to a wrapper around the descriptor factory. By doing the validation early, we make it easier to track down bugs. It also prepares for static type checking which should be done at the usage site. This validation is not yet active and is just logged using monitorCodeUse. This will allow us to clean up callsites which would fail this new type of validation. I chose to copy the validation of abstracting it out since this is just an intermediate step to avoid spamming consoles. This makes more a much cleaner diff review/history. The original validation in the instance will be deleted as soon as we can turn on the warnings. Additionally, getDefaultProps are moved to become a static function which is only executed once. It should be moved to statics but we don't have a convenient way to merge mixins in statics right now. Deferring to ES6 classes. This is still a breaking change since you can return an object or array from getDefaultProps, which later gets mutated and now the shared instance is mutated. Mutating an object that is passed into you from props is highly discouraged and likely to lead to subtle bugs anyway. So I'm not too worried. The defaultProps will later be resolved in the descriptor factory. This will enable a perf optimizations where we don't create an unnecessary object allocation when you use default props. It also means that ReactChildren.map has access to resolved properties which gives them consistent behavior whether or not the default prop is specified.
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:
/** @jsx React.DOM */
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-0.10.0.js"></script>
<!-- In-browser JSX transformer, remove when pre-compiling JSX. -->
<script src="http://fb.me/JSXTransformer-0.10.0.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
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.