Mounting: componentWillMount void componentWillMount() Invoked once, both on the client and server, immediately before the initial rendering occurs. If you call setState within this method, render() will see the updated state and will be executed only once despite the state change.

propTypes object propTypes The propTypes object allows you to validate props being passed to your components. For more information about propTypes, see Reusable Components.

React React is the entry point to the React library. If you're using one of the prebuilt packages it's available as a global; if you're using CommonJS modules you can require() it. React.Component class Component This is the base class for React Components when they're defined using ES6 classes. See Reusable Components for how to use ES6 classes with React. For what methods are actually provided by the base class, see the Component API. React.createClass ReactClass createClass(object spe

replaceProps void replaceProps( object nextProps, [function callback] ) Like setProps() but deletes any pre-existing props instead of merging the two objects. This method is deprecated and will be removed soon. This method is not available on ES6 class components that extend React.Component. Instead of calling replaceProps, try invoking ReactDOM.render() again with the new props. For additional notes, see our blog post about using the Top Level API

When specifying a pixel value for your inline style prop, React automatically appends the string "px" for you after your number value, so this works: var divStyle = {height: 10}; // rendered as "height:10px" ReactDOM.render(<div style={divStyle}>Hello World!</div>, mountNode); See Inline Styles for more info. Sometimes you do want to keep the CSS properties unitless. Here's a list of properties that won't get the automatic "px" suffix: animationIterationCount boxFlex boxFlexGroup b

React.createElement ReactElement createElement( string/ReactClass type, [object props], [children ...] ) Create and return a new ReactElement of the given type. The type argument can be either an html tag name string (eg. 'div', 'span', etc), or a ReactClass (created via React.createClass).

shallowCompare is a helper function to achieve the same functionality as PureRenderMixin while using ES6 classes with React. If your React component's render function is "pure" (in other words, it renders the same result given the same props and state), you can use this helper function for a performance boost in some cases. Example: var shallowCompare = require('react-addons-shallow-compare'); export class SampleComponent extends React.Component { shouldComponentUpdate(nextProps, nextState) {

ReactDOMServer.renderToStaticMarkup string renderToStaticMarkup(ReactElement element) Similar to renderToString, except this doesn't create extra DOM attributes such as data-react-id, that React uses internally. This is useful if you want to use React as a simple static page generator, as stripping away the extra attributes can save lots of bytes.

You can't access the children of your component through this.props.children. this.props.children designates the children being passed onto you by the owner: var App = React.createClass({ componentDidMount: function() { // This doesn't refer to the `span`s! It refers to the children between // last line's `<App></App>`, which are undefined. console.log(this.props.children); }, render: function() { return <div><span/><span/></div>; } })

We've tried to make React as environment-agnostic as possible. People use React in a variety of languages (JavaScript, TypeScript, ClojureScript, etc) and in a variety of environments (web, iOS, Android, NodeJS, Nashorn, etc). There are many tools to help you build great applications. In these sections we introduce some of the tools that are most commonly used together with React. Language Tooling describes how to set up tools like Babel to transpile JSX for a better development experience. P