倒计时（Vue）

startCountdown(customEndTime) {
    const endTime = customEndTime || this.endTime;
    if (!endTime) {
        console.warn('未设置结束时间');
        return;
    }
    const updateFn = () => this.updateCountdown(endTime);
    this.updateCountdown(endTime);
    this.timer = setInterval(updateFn, 1000);
},
updateCountdown(endTime) {
    const now = moment();
    const end = moment(endTime);
    const diff = end.diff(now);
    if (diff <= 0) {
        // 清除定时器
        clearInterval(this.timer);
        this.leaveTimeShow = false;
        this.countdown = { days: 0, hours: 0, minutes: 0, seconds: 0 };
        return;
    }
    this.leaveTimeShow = true;
    const duration = moment.duration(diff);
    this.countdown = {
        days: Math.floor(duration.asDays()),
        hours: duration.hours(),
        minutes: duration.minutes(),
        seconds: duration.seconds()
    };
},