Recurring date using dayjs with dayrs-recur-CodePudding

I’m willing to create a recurring date based on "nth weekday of month" Here is my solution work when I select current Date

let dates = {};
 const currentDate = dayjs();
 const recurrence = currentDate
   .recur(dayjs().add(4, "month"))
   .every("Wednesday")
   .daysOfWeek()
   .every(currentDate.monthWeekByDay())
   .weeksOfMonthByDay();
 recurrence.all().forEach((date) => {
   dates[date.format("YYYY-MM-DD")] = { selected: true, };
 });
// dates = ["2022-09-21","2022-10-19","2022-11-16","2022-12-21","2023-01-18"]

but if put last day of this month which is 30

 let dates = {};

  const lastDayofMonth = dayjs().endOf("month");
  const recurrence = lastDayofMonth
    .recur(dayjs().add(4, "month"))
    .every("Friday")
    .daysOfWeek()
    .every(lastDayofMonth.monthWeekByDay())
    .weeksOfMonthByDay();

I was expecting to get

["2022-09-30","2022-10-28","2022-11-25","2022-12-30"..]

instead of

["2022-09-30","2022-12-30"]

Here is demo

Am I missing something ? Thanks in advance

CodePudding user response：

It possible to create a recurring date based on "nth weekday of month" with dayjs and dayjs-recur as all months as different number of weeks

But there are some challenges:

A month has 4 weeks on average (some months have few or no days for fifth week)
Due to this there may be cases where there is no fifth week or the fifth week doesn't have the nth weekday

To resolve this

If you are getting an nth weekday of month where the week is the last week of the month (could be 4th/5th week)
Get both the nth weekday of month for the last week (5th) and the fourth (4th) week
From the list of dates returned filter if dates for a month occur multiple times and select the latest/greatest one
The filtered result should have the nth weekday of month where the week is the last week of the month

Demo

Below is a link to a working demo forked from @Achraf's demo on code sandbox

Demo Link

Code Example

  const lastDayofMonth = dayjs().endOf("month");

  const recurrence = lastDayofMonth
    .recur(dayjs().add(4, "month"))
    .every("Friday")
    .daysOfWeek()
    .every([3, 4])
    .weeksOfMonthByDay();

  // filter recurrence
  const months = {};
  recurrence.all().forEach((date) => {
    months[date.month()] = date;
  })

  // get filtered dates
  const filteredDates = Object.values(months);

  // formot date into dates object
  filteredDates.forEach((date) => {
    dates[date.format("YYYY-MM-DD")] = { selected: true, color: "#2FB0ED" };
  });

  console.log("dates", dates);
  // ["2022-09-30","2022-10-28","2022-11-25","2022-12-30"..]