languageCode static method

FormFieldValidator<String> languageCode({
  1. RegExp? regex,
  2. List<String> languageCodeWhitelist = const <String>[],
  3. List<String> languageCodeBlacklist = const <String>[],
  4. String? errorText,
  5. bool checkNullOrEmpty = true,
})

FormFieldValidator that requires the field's value to be a valid language code.

Parameters:

  • regex The regex pattern to match.

  • languageCodeWhitelist The list of allowed language codes.

  • languageCodeBlacklist The list of disallowed language codes.

  • errorText The error message when the language code is invalid.

  • checkNullOrEmpty Whether to check for null or empty values. This regex matches a valid language code format.

  • It requires exactly 2 lowercase letters (ISO 639-1 standard).

Examples: en, fr, es

Implementation

static FormFieldValidator<String> languageCode({
  RegExp? regex,
  List<String> languageCodeWhitelist = const <String>[],
  List<String> languageCodeBlacklist = const <String>[],
  String? errorText,
  bool checkNullOrEmpty = true,
}) => LanguageCodeValidator(
  regex: regex,
  languageCodeWhitelist: languageCodeWhitelist,
  languageCodeBlacklist: languageCodeBlacklist,
  errorText: errorText,
  checkNullOrEmpty: checkNullOrEmpty,
).validate;