前端学习（2226）：react之状态

index.js

 

import React from 'react';
import ReactDOM from 'react-dom';


class Clock extends React.Component {
    constructor(props) {
        super(props)
            //状态 时间

        this.state = {
            time: new Date().toLocaleTimeString()
        }
        console.log(this.state.time)
    }
    render() {
        return ( <
            div >
            <
            h1 > 当前时间 { this.state.time } < /h1> < /
            div >

        )

    }
}


setInterval(() => {
    console.log("这是渲染函数")
    ReactDOM.render( < Clock / > , document.querySelector("#root"))
}, 1000);

运行结果