react实现双向绑定

import React from 'react';
export default class APP extends React.Component{
constructor(props){
super(props);
this.state = {
message: ""
}
}

     handelChange = (event) => {
        console.log(event.target);
        this.setState({
            message: event.target.value
        })
     }

render(){
    const mess = this.state.message;
        return(
         <div>
            <input type="text" onChange={this.handelChange} value={mess} />
            <b>{mess}</b>
        </div>
    )
}

}