Enum with extension

main.dart

/*
 * Enum with extension
 * https://gist.github.com/PlugFox/66b37ded0c086c4045143fd2732c099a
 * https://dartpad.dev/66b37ded0c086c4045143fd2732c099a?id=&null_safety=true
 */

enum Country {
  ru,
  gb,
  kz,
  fr,
}

extension CountryX on Country {
  int get code => when<int>(
        ru: 7,
        gb: 44,
        kz: 7,
        fr: 33,
      );

  String get representation => when<String>(
        ru: 'Россия',
        gb: 'Англия',
        kz: 'Казахстан',
        fr: 'Франция',
      );

  T when<T extends Object?>({
    required T ru,
    required T gb,
    required T kz,
    required T fr,
  }) {
    switch (this) {
      case Country.ru:
        return ru;
      case Country.gb:
        return gb;
      case Country.kz:
        return kz;
      case Country.fr:
        return fr;
    }
  }
}