data() {
    return {
      newCurrentTime: '',
      newTimer :null,
    };
  },
methods:{
    this.$post("date001", {}).then(res => {
         let data = res.data.body;
         //当前地区时间
         this.newCurrentTime = data.currentTime;
         //固定开始时间
         let timestamp = data.endTime;
         this.newTimer = setInterval(() => {
            this.newCurrentTime -= 1000;
            //开始时间-当前时间
            let newDayTime = timestamp - this.newCurrentTime;
            if (newDayTime > 1000) {
              //时间戳转时分秒
              var newHour = addZero(Math.floor(newDayTime / Hours)),
              newMinute = addZero(Math.floor((newDayTime % Hours) / Minutes)),
              newSecond = addZero(Math.floor(((newDayTime % Hours) % Minutes) / Seconds));
              if (hour == "00") {
                 this.content = newMinute + "分钟后开始" + newSecond;
               }
              //补零函数
              function addZero(num) {
                return num < 10 ? "0" + num : "" + num;
              }
             }, 1000);
         });
}

timestamp 和 this.newCurrentTime 都console 出来了 确实 timestamp > this.newCurrentTime
并且 this.newCurrentTime 每一秒减少1000
但是 timestamp - this.newCurrentTime 的时候 1秒+1000 这是为啥 都是时间戳