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 lets you use whatever style of data management you want, including mutation. However, if you can use immutable data in performance-critical parts of your application it's easy to implement a fast shouldComponentUpdate() method to significantly speed up your app. Dealing with immutable data in JavaScript is more difficult than in languages designed for it, like Clojure. However, we've provided a simple immutability helper, update(), that makes dealing with this type of data much easier, wi

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

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).

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.

If you know all the properties that you want to place on a component ahead of time, it is easy to use JSX: var component = <Component foo={x} bar={y} />; Mutating Props is Bad If you don't know which properties you want to set, you might be tempted to add them onto the object later: var component = <Component />; component.props.foo = x; // bad component.props.bar = y; // also bad This is an anti-pattern because it means that we can't help you check the right propTypes u

replaceState void replaceState( object nextState, [function callback] ) Like setState() but deletes any pre-existing state keys that are not in nextState. This method is not available on ES6 class components that extend React.Component. It may be removed entirely in a future version of React.

The React add-ons are a collection of useful utility modules for building React apps. These should be considered experimental and tend to change more often than the core. TransitionGroup and CSSTransitionGroup, for dealing with animations and transitions that are usually not simple to implement, such as before a component's removal. LinkedStateMixin, to simplify the coordination between user's form input data and the component's state. cloneWithProps, to make shallow copies of React componen

setProps void setProps( object nextProps, [function callback] ) When you're integrating with an external JavaScript application you may want to signal a change to a React component rendered with ReactDOM.render(). Calling setProps() on a root-level component will change its properties and trigger a re-render. In addition, you can supply an optional callback function that is executed once setProps is completed and the component is re-rendered. This method is deprecated and will be remove

render ReactElement render() The render() method is required. When called, it should examine this.props and this.state and return a single child element. This child element can be either a virtual representation of a native DOM component (such as <div /> or React.DOM.div()) or another composite component that you've defined yourself. You can also return null or false to indicate that you don't want anything rendered. Behind the scenes, React renders a <noscript> tag to work with o