1.通過月份，獲取月份的第一天和最后一天

  getTime(time) {
            var date = new Date(time);
            var new_year = date.getFullYear();    //取當前的年份
            var month = date.getMonth();
            var new_month = month + 1;//取當前的月份
            if (month > 12) {
                new_month -= 12;        //月份減
                new_year++;            //年份增
            }
            var d = new Date(new_year, new_month, 1);                //取當年當月中的第一天
            var lastDay = new Date(d.getTime() - 1000 * 60 * 60 * 24).getDate();//獲取當月最后一天日期
            var cfmStartDate = new_year + '-' + new_month + '-' + "0" + d.getDate();
            var cfmEndDate = new_year + '-' + new_month + '-' + lastDay;
           return cfmStartDate + cfmEndDate
      }

2.獲取一個時間區(qū)間的時間 例如2021-03-12~2021-12-30

getTimeS(time1, time2) {
	 let res = []
     let startTime = new Date(time1).getTime();
     let endTime = new Date(time2).getTime();
     for (var i = startTime; i <= endTime;) {
         res.push(formatTime(i, '-'));
         i += 24 * 60 * 60 * 1000;
     }
     return res
 },
 formatTime(time, spliter) {
   var date = new Date(time);
   var year = date.getFullYear();
   var month = (date.getMonth() + 1) >= 10 ? (date.getMonth() + 1) : '0' + (date.getMonth() + 1);
   var day = date.getDate() >= 10 ? date.getDate() : '0' + date.getDate();
   return year + spliter + month + spliter + day
},

3.獲取當前時間的前一天的時間

getTime() {
  var day1 = new Date();
    day1.setTime(day1.getTime() - 24 * 60 * 60 * 1000);
    return (
      day1.getFullYear() + "-" + (day1.getMonth() + 1) + "-" + day1.getDate()
    );
  },

4.獲取某個時間后的半年時間

function getPastHalfYear(time) {
    var d = new Date(time);
    d.setMonth(d.getMonth() + 1 + 6)
    return d.getFullYear() + "-" + d.getMonth() + "-" + d.getDate()
}