React官网首页的定时器例子,自己琢磨下！

class Timer extends React.Component { constructor(props) { super(props); this.state = {secondsElapsed: 0}; } tick() { this.setState((prevState) => ({ secondsElapsed: prevState.secondsElapsed + 1 })); } componentDidMount() { this.interval = setInterval(() => this.tick(), 1000); } componentWillUnmount() { clearInterval(this.interval); } render() { return ( 
Seconds Elapsed: {this.state.secondsElapsed}
 ); } } ReactDOM.render(, mountNode);

计时器要在componentDidMount生命周期方法挂上，然后在componentWillUnmount生命周期方法清除。

下面是ES6(Class)的语法范例:

componentDidMount() { //this.timer = setInterval(this.tick.bind(this), 50); //或 this.timer = setInterval(() => this.tick(), 50); } componentWillUnmount() { clearInterval(this.timer); } tick() { // 每50ms执行一次 this.setState({ elapsed: new Date() - this.props.start }); }

这个范例是参考自: https://codepen.io/cmymikechu...