getLastWeekNumber method

int getLastWeekNumber(
  1. int year, {
  2. int firstWeekday = DateTime.monday,
})

Returns number of the last week in year.

You can define first weekday (Monday, Sunday or Saturday) with parameter firstWeekday. It should be one of the constant values DateTime.monday, ..., DateTime.sunday.

By default it's DateTime.monday.

See getWeekNumber.

Implementation

int getLastWeekNumber(int year, {int firstWeekday = DateTime.monday}) {
  assert(firstWeekday > 0 && firstWeekday < 8);

  final start = firstDayOfFirstWeek(year, firstWeekday: firstWeekday);
  final end = firstDayOfWeek(DateTime(year, DateTime.december, 31), firstWeekday: firstWeekday);
  final diffInDays = getDaysDifference(end, start);
  var res = diffInDays ~/ DateTime.daysPerWeek;
  if (isWeekInYear(end, year, firstWeekday)) res++;
  return res;
}