React(组件间通信--父级向子级传递消息)

父级把"12"传递给子级

import React, { Component } from 'react';

class Ch extends React.Component{
    constructor(...args){
        super(...args)
        
    }
    render(){
        return <div>{this.props.a}</div>
    }
}

class Fa extends React.Component{
    constructor(...args){
        super(...args)
        this.a=12
    }
    render(){
        return <div><Ch a={this.a}/></div>
        //令:父级.a=子级.props.a
    }
}
export default Fa;