activityDateToJson function
Converts a Map<String, dynamic> object to a Firestore map. Used for activities.
Implementation
Map<String, Timestamp> activityDateToJson(
(DateTime? startDate, DateTime? endDate) date,
) =>
{
'startDate': Timestamp.fromDate(date.$1 ?? DateTime.now()),
'endDate': Timestamp.fromDate(date.$2 ?? DateTime.now()),
};