Demonstrates pattern matching with Dart 2.17 enums

dart-enum-pattern-matching.dart

enum Key {
  
  key1('key1'),
  key2('key2');
  
  final String value;
  const Key(this.value);
  
  T mapFor<T>({
    required T Function() key1,
    required T Function() key2,
  }) {
    if (value == Key.key1.value) {
      return key1();
    } else if (value == Key.key2.value) {
      return key2();
    }
    throw Exception('Unexpected value for `value` of "$value" - did you forget to add a handler here?');
  }
}

void main() {
  Key key = Key.key1;
  key.mapFor(
    key1: () => print('This was key1'),
    key2: () => print('This was key2'),
  );
}