isValidCardExpireYear function
return an error message if value does not pass the validation validation requires val: not equal null
Implementation
String? isValidCardExpireYear(String? val) {
if (isNotNull(val) == null) {
final year = DateTime.now().year - 2000;
if (int.parse(val ?? "") < year) return "valid year is required";
return null;
}
return isNotNull(val);
}