React 父子组件通信

1、子组件调用父组件方法

父组件html

<div>
    <Chlid link={this.fn()} />
</div>      

父组件js

fn= e => {
   console.log(e)  //123
  };      

子组件html

<div onClick={() => {
  this.props.link(123);
}}>点击事件</div>      

<div>
    <Chlid link={(e) => {
        this.child = e;
    }} 
/></div>

<div onClick={() => {
     this.child.fn(123);
}}>点击事件</div>      

componentDidMount(){
    this.props.link(this)
}

fn= (e) => {
    console.log(e);
};