js获取昨天，最近7天，最近30天通用方法

 function formatDate (val) {

   // 格式化时间

   let start = new Date(val)

   let y = start.getFullYear()

   let m = (start.getMonth() + 1) > 10 ? (start.getMonth() + 1) : '0' + (start.getMonth() + 1)

   let d = start.getDate() > 10 ? start.getDate() : '0' + start.getDate()

   return y + '-' + m + '-' + d

 }

 function mistiming (sDate1, sDate2) {

   // 计算开始和结束的时间差

   let aDate, oDate1, oDate2, iDays

   aDate = sDate1.split('-')

   oDate1 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])

   aDate = sDate2.split('-')

   oDate2 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])

   iDays = parseInt(Math.abs(oDate1 - oDate2) / 1000 / 60 / 60 / 24)

   return iDays + 1

 }

 function countDate (start, end) {

   // 判断开始和结束之间的时间差是否在90天内

   let days = mistiming(start, end)

   let stateT = days > 90 ? Boolean(0) : Boolean(1)

   return {

     state: stateT,

     day: days

   }

 }

 function timeForMat (count) {

   // 拼接时间

   let time1 = new Date()

   time1.setTime(time1.getTime() - (24 * 60 * 60 * 1000))

   let Y1 = time1.getFullYear()

   let M1 = ((time1.getMonth() + 1) > 10 ? (time1.getMonth() + 1) : '0' + (time1.getMonth() + 1))

   let D1 = (time1.getDate() > 10 ? time1.getDate() : '0' + time1.getDate())

   let timer1 = Y1 + '-' + M1 + '-' + D1 // 当前时间

   let time2 = new Date()

   time2.setTime(time2.getTime() - (24 * 60 * 60 * 1000 * count))

   let Y2 = time2.getFullYear()

   let M2 = ((time2.getMonth() + 1) > 10 ? (time2.getMonth() + 1) : '0' + (time2.getMonth() + 1))

   let D2 = (time2.getDate() > 10 ? time2.getDate() : '0' + time2.getDate())

   let timer2 = Y2 + '-' + M2 + '-' + D2 // 之前的7天或者30天

   return {

     t1: timer1,

     t2: timer2

   }

 }

 function yesterday (start, end) {

   // 校验是不是选择的昨天

   let timer = timeForMat(1)

   return timer

 }

 function sevenDays () {

   // 获取最近7天

   let timer = timeForMat(7)

   return timer

 }

 function thirtyDays () {

   // 获取最近30天

   let timer = timeForMat(30)

   return timer

 }

 export {

   formatDate,

   countDate,   yesterday,

   sevenDays,

   thirtyDays

 }