validator method

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

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

Implementation

@override
NumberDocumentError? validator(String value) {
  final trimmed = value.trim();
  if (trimmed.isEmpty) return NumberDocumentError.empty;
  if (trimmed.length < minLength) return NumberDocumentError.tooShort;
  if (maxLength != null && trimmed.length > maxLength!) {
    return NumberDocumentError.tooLong;
  }

  return null;
}