实时显示时间

<div id="app">
    {{Showtime}}
</div>
<script>
    var vm = new Vue({
        el: "#app",
        data: {
            Showtime:"",
            clearTime:null, 
        },
        created() {
            // 让页面一开始就加载就显示时间。
            //解决隔1s后才显示时间这个问题
            let newtime = new Date();
            let myHover = newtime.getHours();
            let myMin = newtime.getMinutes();
            this.Showtime = myHover + ":" + myMin;
            // 让后每隔1s跟新时间
            this.runTime();
        },
        methods: {
            runTime() {
                this.clearTime = setInterval(() => {
                    let newtime = new Date();
                    let myHover = newtime.getHours();
                    let myMin = newtime.getMinutes();
                    this.Showtime = myHover + ":" + myMin;
                }, 1000)
            }
        },
        //离开页面清除定时器
        beforeDestroy(){
           clearInterval( this.clearTime);
           console.log("---")
        }  
    })
</script>