MomentJS - 获取日期范围给出一个月中的特定日期

Question

Given day of the month of 5 how would you best get the date range between the 5th of last/this month and the next 5th of the month?

// given today is May 24 2021
// should return May 5 - June 5
function getDateRange(selectedDay) {
  const today = moment()
  let previous, next
  if (today.date() >= selectedDay) {
    previous = today.clone().set('date', selectedDay)
    next = today.clone().add(1, 'months').set('date', selectedDay)
  }
  else {
    previous = today.clone().subtract(1, 'months').set('date', selectedDay)
    next = today.clone().set('date', selectedDay)
  }

  return [ previous, next ]
}

This works most of the time except for when the selected day doesn't exist for the month (ie. 31st).

For example, if today's date was Feb 15, 2021 and the selectedDay is 31 , the function should return Jan 31 - Feb 28 .

Does anyone have an elegant solution to this?

Answer 1

I edit a bit your code and insert a function to determiante the max date of the month.

 // To force a date I inserted a initDate like parameters, remove it if it's unnecessary function getDateRange(selectedDay, initDate) { const today = moment(initDate); let previous; let next; if (today.date() >= selectedDay) { previous = moment(today).startOf('month'); next = moment(today).add(1, 'month').startOf('month'); } else { previous = moment(today).subtract(1, 'months'); next = moment(today); } previous = limiter(previous, selectedDay); // this function get the max date of the month next = limiter(next, selectedDay); return [previous, next]; } function limiter(dateToLimit, selectedDay) { if (moment(dateToLimit).endOf('month').isBefore(moment(dateToLimit).date(selectedDay))) dateToLimit = moment(dateToLimit).endOf('month'); else dateToLimit = moment(dateToLimit).date(selectedDay); return dateToLimit; } console.log(getDateRange(31, '2021-02-15')); console.log(getDateRange(31, '2021-03-15')); console.log(getDateRange(13, '2021-02-15')); console.log(getDateRange(13, '2021-09-15')); console.log(getDateRange(26, '2021-09-15')); console.log(getDateRange(26, '2021-09-27'));

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