js 获取指定月份天数

getDayArrayByMonth() {
  this.time = '2021-09'  or  '2021-09-01'
  const date = new Date(this.time)
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = new Date(year, month, 0)
  const dayCounts = day.getDate()  //  指定月份天数
  let monthDayList = []
  for (var i = 0; i < dayCounts; i++) {
    monthDayList.push(String(i + 1))
  }
  this.currentMonthDayList = monthDayList
},

生成数组结果