react中运用JS中setTimeout时间计时的方法

<span id="clock" style={{display:'block',fontSize:"14px",paddingTop:'10px'}}></span>

  componentDidMount(){
        function getTime(){
            // const $this=this;
            let data=new Date()
            let hour=data.getHours()<10?"0"+data.getHours():data.getHours();
            let minutes=data.getMinutes()<10?"0"+data.getMinutes():data.getMinutes();
            let seconds=data.getSeconds()<10?"0"+data.getSeconds():data.getSeconds();
            let time=hour+":"+minutes+":"+seconds;
            document.getElementById('clock').innerHTML=time;
            console.log(time);
            // return hour+":"+minutes+":"+seconds;
            setTimeout(getTime,1000);
        }
        getTime();

    }