kDefaultToMonthly function Views
Carry-focus date when switching to a month view, derived from old.
Implementation
FloatingDateTime kDefaultToMonthly(ViewController old) {
final oldRange = old.floatingVisibleRange.value!;
return switch (old.viewConfiguration) {
MonthViewConfiguration _ => FloatingDateTime.fromDateTime(oldRange.dominantMonthDate),
MultiDayViewConfiguration _ => oldRange.start,
ScheduleViewConfiguration _ => oldRange.start,
_ => FloatingDateTime.fromDateTime(oldRange.dominantMonthDate),
};
}