JS 计算两个时间戳相差年月日时分秒

// 计算两个时间戳相差的多少年多少月多少天

calculateDiffTime() {

  let startTime = '1629107469000'  //2021-08-16 17:51

  let endTime = '1976262719000'  //2032-08-16 17:51

  let flag = [1, 3, 5, 7, 8, 10, 12, 4, 6, 9, 11, 2];

  let start = new Date(startTime);

  let end = new Date(endTime);

  let year = end.getFullYear() - start.getFullYear();

  let month = end.getMonth() - start.getMonth();

  let day = end.getDate() - start.getDate();

  if (month < 0) {

    year--;

    month = end.getMonth() + (12 - start.getMonth());

  }

  if (day < 0) {

    month--;

    let index = flag.findIndex((temp) => {

      return temp === start.getMonth() + 1

    });

    let monthLength;

    if (index <= 6) {

      monthLength = 31;

    } else if (index > 6 && index <= 10) {

      monthLength = 30;

    } else {

      monthLength = 28;

    }

    day = end.getDate() + (monthLength - start.getDate());

  }

  this.result = `相差${year}年${month}月${day}天`;

  console.log(this.result)

}

#  计算两个时间戳相差的多少年多少月多少天多少小时多少分多少秒（另一种写法）

//计算两个时间戳相差的多少年多少月多少天多少小时多少分多少秒

calculateDiffTime (){

  let startTime = '1629107469000'  //2021-08-16 17:51

  let endTime = '1976262719000'  //2032-08-16 17:51

  let runTime = parseInt((endTime - startTime) / 1000);

  var year = Math.floor(runTime / 86400 / 365);

  runTime = runTime % (86400 * 365);

  var month = Math.floor(runTime / 86400 / 30);

  runTime = runTime % (86400 * 30);

  var day = Math.floor(runTime / 86400);

  runTime = runTime % 86400;

  var hour = Math.floor(runTime / 3600);

  runTime = runTime % 3600;

  var minute = Math.floor(runTime / 60);

  runTime = runTime % 60;

  var second = runTime;

  console.log(`相差${year}年${month}月${day}天${hour}小时${minute}分${second}秒`);

　return year+','+month+','+day+','+hour+','+minute+','+second;

}