validateYear method

String? validateYear(
  1. String value, {
  2. String? errorMessage,
  3. String? errorMessage2,
})

Implementation

String? validateYear(String value,
    {String? errorMessage, String? errorMessage2}) {
  if (value.isEmpty)
    return errorMessage ?? errorEmpty;
  else if (value.length != 4) return errorMessage2 ?? 'Not valid';
  return null;
}