react实现计数器

     var In=({display})=><div>{display}</div>;
     var Btn=({click})=><button onClick={click}>-</button>
     class Davinci extends React.Component
      {
          constructor(props) {
            super(props)
          
            this.state = {
               count:100
            };
            this.clickfunc=this.clickfunc.bind(this);

          };
        clickfunc=function(){
            this.setState({
                count:this.state.count-1,
            })
        } 
       render() {
         return (
           <div>
             <In display={this.state.count}/>
             <Btn click={this.clickfunc}/>
           </div>
         )
       }
     }
     ReactDOM.render(
            <div>
                <Davinci/>
            </div>
            , document.querySelector('#container')
        )