vue实时显示当前时间且转化为“yyyy-MM-dd hh:mm:ss”格式

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>vue实时显示当前时间显示</title>
    <link rel="stylesheet" href="../css/reset.css">
    <script src="../js/jquery/jquery-3.1.1.min.js"></script>
    <script src="../js/vue/vue.js"></script>
</head>
<body >
<div id="app">当前实时时间:{{dateFormat(date)}}</div>
<script>
    var vm=new Vue({
        el:"#app",
        data:{
            date:new Date()
        },
        mounted () {
            var _this = this; //声明一个变量指向vue实例this,保证作用域一致
            this.timer = setInterval(function() {
                _this.date = new Date();//修改数据date
            }, 1000);
        },
        beforeDestroy () {
            if(this.timer) {
                clearInterval(this.timer);//在vue实例销毁钱，清除我们的定时器
            }
        },
        methods:{
            //时间格式化函数，此处仅针对yyyy-MM-dd hh:mm:ss 的格式进行格式化
            dateFormat(time) {
                var date=new Date(time);
                var year=date.getFullYear();
                /* 在日期格式中，月份是从0开始的，因此要加0
                 * 使用三元表达式在小于10的前面加0，以达到格式统一  如 09:11:05
                 * */
                var month= date.getMonth()+1<10 ? "0"+(date.getMonth()+1) : date.getMonth()+1;
                var day=date.getDate()<10 ? "0"+date.getDate() : date.getDate();
                var hours=date.getHours()<10 ? "0"+date.getHours() : date.getHours();
                var minutes=date.getMinutes()<10 ? "0"+date.getMinutes() : date.getMinutes();
                var seconds=date.getSeconds()<10 ? "0"+date.getSeconds() : date.getSeconds();
                // 拼接
                return year+"-"+month+"-"+day+" "+hours+":"+minutes+":"+seconds;
            }
        }
    })
</script>
</body>
</html>