date static method
Validates a date string in various formats.
Implementation
static String? date(String? value, {String format = 'yyyy-MM-dd'}) {
if (value == null || value.isEmpty) return 'Date is required';
try {
final date = DateTime.parse(value);
if (date.isAfter(DateTime.now())) {
return 'Date cannot be in the future';
}
return null;
} catch (e) {
return 'Invalid date format. Use $format';
}
}