vue列表数据倒计时存在的一些坑

vue 列表数据倒计时，在页面销毁前需要清除定时器，否着会报错。

  export default {
    data() {
      return {
        list: []
      }
    },
    mounted() {
      for (let i in this.list) {
        this.countDown(i)
      }
    },
    destroyed() {
     // 在这个生命周期中清除定时器
      for (let i in this.list) {
        clearInterval(this.list[i].countDownFn);
      }
    },
    methods: {
      formatTime(s) {
        let Day = parseInt(s / 60 / 60 / 24, 10)
        let Hour = parseInt(s / 60 / 60 % 24, 10)
        let Minute = parseInt(s / 60 % 60, 10)
        let Second = parseInt(s % 60, 10)
        let res = {
          d: Day,
          h: (Hour + "").padStart(2, "0"),
          m: (Minute + "").padStart(2, "0"),
          s: (Second + "").padStart(2, "0")
        }
        return res;
      },
      countDown(i) {
        let item = this.list[i]
        this.list[i].countDownFn = setInterval(() => {
          item.time_remaining -= 1
          if (item.time_remaining <= 0) {
            clearInterval(this.list[i].countDownFn);
          } else {
            item.countDownTime = item.time_remaining > 0 ? this.formatTime(item.time_remaining) : {}
          }
        }, 1000);
      }
    }
  }