获取当前日期前后某年/月/日/时/分/秒的日期；当前月或者前后某月开始结束日期；当前周或者前后某周开始结束日期；

获取当前日期前后某年/月/日/时/分/秒的日期

/*
* 获取当前时间或者，某个时间
* time - 某个时刻， 默认当前时间
* type - year/mnth/day/hours/minutes/seconds
* num - 某个时间之前或者之后几年/月/日/时/分/秒的Date; 整数
*/
function getTimeCustom (time, type = 'day', num) {
  const date = time ? new Date(time) : new Date()
  if (type === 'year') {
    date.setFullYear(date.getFullYear() + num)
  } else if (type === 'month') {
    date.setMonth(date.getMonth() + num)
  } else if (type === 'day') {
    date.setDate(date.getDate() + num)
  } else if (type === 'hours') {
    date.setHours(date.getHours() + num)
  } else if (type === 'minutes()') {
    date.setMinutes(date.getMinutes() + num)
  } else if (type === 'seconds') {
    date.setSeconds(date.getSeconds() + num)
  }
  return date
}

获取当前月或者前后某月开始结束日期

转自blog.csdn.net/WICHER_WU/a… ;然后并稍加修改

/**
 *获得距离当前前后某月的开始日期和结束日期
 * month 整数，负数当前之前某月，正数当月之后某月，0当月
*/
 function getMonthStartDateAndDateRange (month = 0) {
  const oneDayLong = 24 * 60 * 60 * 1000
  const now = new Date()
  now.setMonth(now.getMonth() + month)
  const year = now.getFullYear()
  const monthStartDate = new Date(year, now.getMonth(), 1) // 当前月1号
  const nextMonthStartDate = new Date(year, now.getMonth() + 1, 1) // 下个月1号
  const days = (nextMonthStartDate.getTime() - monthStartDate.getTime()) / oneDayLong // 计算当前月份的天数
  const monthEndDate = new Date(year, now.getMonth(), days)
  const monthRange = [monthStartDate, monthEndDate]
  return monthRange
}

获取当前周或者前后某周开始结束日期

转自blog.csdn.net/WICHER_WU/a…

/**
 * 获得本周的开始日期和结束日期
 */
function getWeekStartDateAndEndDateRange () {
  const oneDayLong = 24 * 60 * 60 * 1000
  const now = new Date()
  const mondayTime = now.getTime() - (now.getDay() - 1) * oneDayLong
  const sundayTime = now.getTime() + (7 - now.getDay()) * oneDayLong
  const monday = new Date(mondayTime)
  const sunday = new Date(sundayTime)
  const weekRange = [monday, sunday]
  return weekRange
}