微信小程序倒计时

wxml
<view class="count-time_cont">
  <view>{{day}}</view>天
  <view>{{hour}}</view>时
  <view>{{minute}}</view>分
  <view>{{secondsec}}</view>秒
</view>

wxss
.count-time_cont {
  display: flex;
}

js
Component({
  properties: {},
  data: {
    gmtDate: '2021-1-15 00:00:00',
    day: 0,
    hour: 0,
    minute: 0,
    secondsec: 0
  },
//组件呗调动的时候运行倒计时
  attached: function () {
    this.countDown()
  },
  methods: {
    countDown() {
      var that = this;
      var nndate = Date.parse(that.data.gmtDate)
      let timeLeft = nndate - new Date();
      var d, h, m, s, ms;
      if (timeLeft >= 0) {
        d = Math.floor(timeLeft / 1000 / 60 / 60 / 24);
        h = Math.floor(timeLeft / 1000 / 60 / 60 % 24);
        m = Math.floor(timeLeft / 1000 / 60 % 60);
        s = Math.floor(timeLeft / 1000 % 60);
        ms = Math.floor(timeLeft % 1000);
        ms = ms < 100 ? "0" + ms : ms
        var str = ms.toString();
        ms = str.substr(0, 2);
        s = s < 10 ? "0" + s : s
        m = m < 10 ? "0" + m : m
        h = h < 10 ? "0" + h : h
        d = d < 10 ? "0" + d : d
        that.setData({
          day: d,
          hour: h,
          minute: m,
          secondsec: s
        })
　　//递归
        setTimeout(() => {
          that.countDown()
        }, 1000);
      } else {
        that.setData({
          day: '00',
          hour: '00',
          minute: '00',
          secondsec: '00'
        })
        console.log('已截止')
      }
    }
  },

})