javscript获取本周的开始日期和结束日期（包括上一周、下一周）

代码封装：

function getWeek(n, type) {
  let now = new Date()
  let day = now.getDay() //返回星期几的某一天;
  if (!type) {
	if (n == 1) {
	  let dayNumber = day == 0 ? 0 : 7 - day
	  now.setDate(now.getDate() + dayNumber + 1)
	} else if (n == -1) {
	  let dayNumber = day == 0 ? 6: day - 1
	  now.setDate(now.getDate() - dayNumber - 7)
	} else {
	  let dayNumber = day == 0 ? 6: day - 1
	  now.setDate(now.getDate() - dayNumber)
	}
  } else {
	if (n == 1) {
	  let dayNumber = day == 0 ? 0 : 7 - day
	  now.setDate(now.getDate() + dayNumber + 1 + 6) // 在周开始的日期上+6天=周结束
	} else if (n == -1) {
	  let dayNumber = day == 0 ? 6: day - 1
	  now.setDate(now.getDate() - dayNumber - 7 + 6)
	} else {
	  let dayNumber = day == 0 ? 0: 7 - day
	  now.setDate(now.getDate() + dayNumber)
	}
  }
  let date = now.getDate()
  let month = now.getMonth() + 1

  let s = now.getFullYear() + '-' + (month < 10 ? '0' + month : month) + '-' + (date < 10 ? '0' + date : date)
  return s
}

调用方法：

console.log('获取本周开始日期：', getWeek(0, 0))
console.log('获取本周结束日期：', getWeek(0, 1))

//注：上一周开始日期getWeek(-1, 0)，下一周开始日期getWeek(1, 0)