getLastWeekNumber static method
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
static int getLastWeekNumber(int year, {int? firstWeekday}) {
assert(firstWeekday == null || 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;
}