无状态函数—可以用 JavaScript 函数来定义你的 React 类。

    1. var  HelloMessage = React.createClass({
    2.    render:function(){ return <div>Hello { this.props.name }</div> }
    3. })
    4. // 等价于：
    5. function HelloMessage(props){
    6.    return <div>Hello { props.name }</div>
    7. }
    9. var ComponentWithDefaultProps = React.createClass({
    10.    getDefaultProps :function(){
    11.       return { value:'default value' }
    12.    }
    13. });
    14. //getInitialState
    1. export class Counter extends React.Component {
    2.   constructor(props) {
    3.     super(props);
    4.     this.state = {count: props.initialCount};
    5.     this.tick = this.tick.bind(this);
    6.   }
    7.   tick() {
    8.     this.setState({count: this.state.count + 1});
    9.   }
    10.   render() {
    11.     return (
    12.       <div onClick={ this.tick }>
    13.         Clicks: {this.state.count}
    14.       </div>
    15.     );
    16.   }
    17. }
    18. Counter.propTypes = { initialCount: React.PropTypes.number };
    19. Counter.defaultProps = { initialCount: 0 };