isWeekend function
Checks if the given date falls on a weekend (Saturday or Sunday).
date - The date to check.
Returns true if the date is Saturday or Sunday.
Example:
final saturday = DateTime(2024, 1, 20);
print(isWeekend(saturday)); // true
final monday = DateTime(2024, 1, 15);
print(isWeekend(monday)); // false
Implementation
bool isWeekend(DateTime date) =>
date.weekday == DateTime.saturday || date.weekday == DateTime.sunday;