js 獲取某月第一天和最後一天

1、獲取某月第一天和最後一天日期

function getDateByMonth (timeStamp) {
  let inDate = new Date(timeStamp)
  let year = inDate.getFullYear()
  let month = inDate.getMonth()
  let startTime = new Date(year, month, 1).getTime()
  let endTime =  new Date(year, month + 1, 0).getTime()
  return {
    startTime: startTime,
    endTime: endTime
  }
}

2、獲取某月第一天和最後一天時間戳

/** 根據時間戳 獲取其月開始時間戳和結束時間戳 */
function getTimeStamp (timeStamp) {
  let inDate = new Date(timeStamp)
  let year = inDate.getFullYear()
  let month = inDate.getMonth()
  let startTime = new Date(year, month, 1).getTime()
  let endTime =  new Date(year, month + 1, 1).getTime() - 1
  return {
    startTime: startTime,
    endTime: endTime
  }
}