Implementation code of countdown in WeChat applet

timeFormat: function(param) { //小于10的格式化函数
    return param < 10 ? '0' + param : param;
  },
  countDown: function() { //倒计时函数
    // 获取当前时间，同时得到活动结束时间数组
    let newTime = Date.parse(new Date());
    let endTimeList = this.data.actEndTimeList;
    let countDownArr = [];
    // 对结束时间进行处理渲染到页面
    endTimeList.forEach(o => {
      var strtime = o.replace(/-/g, '/');
      strtime = strtime.substring(0, 19);
      let endTime = new Date(strtime).getTime();
      let obj = null;
      // 如果活动未结束，对时间进行处理
      if (endTime - newTime > 0) {
        let time = (endTime - newTime) / 1000;
        // 获取天、时、分、秒
        let day = parseInt(time / (60 * 60 * 24));
        let hou = parseInt(time % (60 * 60 * 24) / 3600);
        let min = parseInt(time % (60 * 60 * 24) % 3600 / 60);
        let sec = parseInt(time % (60 * 60 * 24) % 3600 % 60);
        obj = {
          day: this.timeFormat(day),
          hou: this.timeFormat(hou),
          min: this.timeFormat(min),
          sec: this.timeFormat(sec)
        }
      } else { //活动已结束，全部设置为'00'
        obj = {
          day: '00',
          hou: '00',
          min: '00',
          sec: '00'
        }
      }
      countDownArr.push(obj);
    })
    // 渲染，然后每隔一秒执行一次倒计时函数
    this.setData({
      countDownList: countDownArr
    })
    setTimeout(this.countDown, 1000);
  },