validator method
- String? value
override
A function that must return a validation error if the provided
value is invalid and null otherwise.
Implementation
@override
TaxIdValidationError? validator(String? value) {
if (value == null || value.trim().isEmpty) {
return TaxIdValidationError.empty;
} else if (!AppRegExp.taxIdRegExp.hasMatch(value)) {
return TaxIdValidationError.invalid;
} else {
return null;
}
}