Working days

Package: DATETIME_PACKAGE. Registered by createEngine(); for a slimmer engine, register it explicitly (see choosing packages).

A working day is a weekday, a day an office is open, so a deadline measured in working days skips the weekends in between. Solve counts them forward or back from a date, or across a window, and excludes public holidays too when the host supplies a calendar.

Deadlines count working days, not calendar days. Weekends are always skipped. An offset counts forward or back to a working day, and between counts the working days in a window, both ends included.

25/12/2023 + 5 workdays // Monday, January 1, 2024
working days between 01/01/2024 and 31/01/2024 // 23
workdays in 3 weeks // 15

3 business days from today

working and business days mean the same thing, and either reads in the singular for a count of one (1 working day after ...).

Public holidays

Holidays cannot be worked out from a date the way a weekend can: they depend on the region and change year to year. So the engine excludes them only when the host application supplies a calendar, the same way it takes a data source for stocks or weather. Left unconfigured, working-day arithmetic skips weekends only, and says as much rather than guessing a holiday it was never told about.

A host passes the calendar as a list of dates or a predicate function:

new ExpressionEngine({
  config: { date: { holidays: ["2024-12-25", "2024-12-26"] } },
});
// or: { date: { holidays: (date) => isPublicHoliday(date) } }

With that calendar, 1 working day after 24/12/2024 steps over the 25th and 26th to the 27th, and working days between ... leaves them out of the count. The offset forms, between, and <date> + N workdays all consult it.

workdays in <span> and the is a workday / is a weekend questions stay weekends-only either way: the first has no date to look a holiday up on, and the second reports the shape of the week (is this a weekday), not whether a particular office is open.