validator method

  1. @override
CountryCodeError? validator(
  1. String value
)
override

A function that must return a validation error if the provided value is invalid and null otherwise.

Implementation

@override
CountryCodeError? validator(String value) {
  if (value.trim().isEmpty) return CountryCodeError.empty;
  if (!validCodes.contains(value)) return CountryCodeError.invalid;

  return null;
}