react生命周期

import ReactDom from 'react-dom';
class LifeCycle extends React.Component {
    constructor(props) {
        super(props);
        alert("Initial render");
        alert("constructor");
        this.state = {str: "hello"};
    }
 
    componentWillMount() {
        alert("componentWillMount");
    }
 
    componentDidMount() {
        alert("componentDidMount");
    }
 
    componentWillReceiveProps(nextProps) {
        alert("componentWillReceiveProps");
    }
 
    shouldComponentUpdate() {
        alert("shouldComponentUpdate");
        return true;        // 记得要返回true
    }
 
    componentWillUpdate() {
        alert("componentWillUpdate");
    }
 
    componentDidUpdate() {
        alert("componentDidUpdate");
    }
 
    componentWillUnmount() {
        alert("componentWillUnmount");
    }
 
    setTheState() {
        let s = "hello";
        if (this.state.str === s) {
            s = "HELLO";
        }
        this.setState({
            str: s
        });
    }
 
    forceItUpdate() {
        this.forceUpdate();
    }
 
    render() {
        alert("render");
        return(
            <div>
                <span>{"Props:"}<h2>{parseInt(this.props.num)}</h2></span>
                <br />
                <span>{"State:"}<h2>{this.state.str}</h2></span>
            </div>
        );
    }
}
 
class Container  extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            num: Math.random() * 100
        };
    }
 
    propsChange() {
        this.setState({
            num: Math.random() * 100
        });
    }
 
    setLifeCycleState() {
        this.refs.rLifeCycle.setTheState();
    }
 
    forceLifeCycleUpdate() {
        this.refs.rLifeCycle.forceItUpdate();
    }
 
    unmountLifeCycle() {
        // 这里卸载父组件也会导致卸载子组件
        React.unmountComponentAtNode(document.getElementById("container"));
    }
 
    parentForceUpdate() {
        this.forceUpdate();
    }
 
    render() {
        return (
            <div>
                <a href="javascript:;" className="weui_btn weui_btn_primary" onClick={this.propsChange.bind(this)}>propsChange</a>
                <a href="javascript:;" className="weui_btn weui_btn_primary" onClick={this.setLifeCycleState.bind(this)}>setState</a>
                <a href="javascript:;" className="weui_btn weui_btn_primary" onClick={this.forceLifeCycleUpdate.bind(this)}>forceUpdate</a>
                <a href="javascript:;" className="weui_btn weui_btn_primary" onClick={this.unmountLifeCycle.bind(this)}>unmount</a>
                <a href="javascript:;" className="weui_btn weui_btn_primary" onClick={this.parentForceUpdate.bind(this)}>parentForceUpdateWithoutChange</a>
                <LifeCycle ref="rLifeCycle" num={this.state.num}></LifeCycle>
            </div>
        );
    }
}
 
ReactDom.render(
    <Container></Container>,
    document.getElementById('root')
);