vue实现秒杀倒计时组件

<template>
  <div>
      <input type="datetime-local" :min="currentTime" placeholder="请输入秒杀开始时间" v-model="startTime">
      <button @click="submit">开始计时</button>
  </div>
  <div>
      <h1>{{ countDownTime }}</h1>
  </div>
</template>

<script>
let timer = null;
let tipTextPrefix = '离秒杀开始还有： ';
import moment from "moment";
export default {
    name: 'CountDown',
    data() { return {
        currentTime: moment().format('YYYY-MM-DDTHH:mm'), // 请使用步骤1-3计算出来的服务器时间
        startTime: moment().format('YYYY-MM-DDTHH:mm'),
        countDownTime: tipTextPrefix + '0天 0小时 0分钟 0秒'
    }},
    methods: {
        submit: function() {
            const _this = this;
            clearInterval(timer);
            timer = setInterval(() => {
                _this.countDownTime = _this.countDown();
            }, 1000);
        },
        countDown: function() {
            console.log(this.startTime);
            const seconds = moment(this.startTime).diff(new Date, 'seconds');
            if (seconds <= 0) {
                clearInterval(timer);
                return '秒杀已开始';
            }
            const second = seconds%60;
            const minutes = (seconds-second) / 60;
            const minute = minutes%60;
            const hours = (minutes-minute) / 60;
            const hour = hours%24;
            const day = (hours-hour) / 24;
            const res = tipTextPrefix + day + '天 '+ hour + '小时 '+ minute + '分钟 '+ second + '秒 ';
            return res;
        }
    },
}
</script>

<style>

</style>