现在时间到某一个时间的倒计时

// getEndTime('2017/10/22 15:00:00')
const getEndTime = endTime => {
    let startDate = new Date();  //开始时间，当前时间
    let endDate = new Date( endTime ); //结束时间，需传入时间参数
    let t = endDate.getTime() - startDate.getTime();  //时间差的毫秒数
    let d = 0, h = 0, m = 0, s = 0;
    if( t >= 0 ) {
      d = Math.floor( t/1000/3600/24 );
      h = Math.floor( t/1000/60/60%24 );
      m = Math.floor( t/1000/60%60 );
      s = Math.floor( t/1000%60 );
    }
    return `剩余时间${d}天${h}时${m}分${s}秒`
}