Kday - functions to return the date of the first, last or nth day of the week on, nearest, before or after a given date

kday is a simple, no-dependencies library to calculate the date of the first, last or nth day of the week on, nearest, before or after a given date. The code is extracted from ex_cldr_calendars so has been in production for several years and therefore considered stable.

Functions

• first_kday(date, k) - Return the date of the first day_of_week on or after the specified date.

• kday_after(date, k) - Return the date of the day_of_week after the specified date.

• kday_before(date, k) - Return the date of the day_of_week before the specified date.

• kday_nearest(date, k) - Return the date of the day_of_week nearest the specified date.

• kday_on_or_after(date, k) - Return the date of the day_of_week on or after the specified date.

• kday_on_or_before(date, k) - Return the date of the day_of_week on or before the specified date.

• last_kday(date, k) - Return the date of the last day_of_week on or before the specified date.

• nth_kday(date, n, k) - Return the date of the nth day_of_week on or before/after the specified date.

Examples

Days of the week follow the elixir convention of 1 being Monday and 7 being Sunday.

# Memorial Day in the US
iex> Kday.last_kday(~D[2017-05-31], 1)
~D[2017-05-29]

iex> Kday.kday_nearest(~D[2016-02-29], 2)
~D[2016-03-01]

iex> Kday.kday_on_or_after(~D[2017-11-30], 1)
~D[2017-12-04]