StringId - a dynamic key lookup

[vishna]

In some cases you might want to be able to use strings in more dynamic manner, e.g. backend driven a/b test.

Since dart on flutter offers no reflection we could generate extension method that could achieve that.

class StringKeys {
  StringKeys._();
  static const carrot = "carrot";
  static const apple = "apple";
}

extension StringKeysExtension on S {
  dynamic operator [](String key) {
    switch(key) {
      case StringKeys.carrot: return carrot;
      case StringKeys.apple: return apple;
      default: return null;
    }
  }
}

You could then use it in your code:

final apple1 = strings.apple;
final apple2 = strings["apple"];
final apple3 = strings[StringKeys.apple];

Beware the returned apple might not be a string value but a function in which case you need to know what arguments you want to use.

[vishna]

...or a bit more rigid version

class StringId {
  const StringId(this.value);
  final String value;
  static const onboarding_sell_photos = StringId("onboarding_sell_photos");
  static const mission_winners = StringId("mission_winners");
}

extension StringKeysExtension on S {
  dynamic operator [](StringId id) {
    switch(id.value) {
      case "onboarding_sell_photos": return onboarding_sell_photos;
      case "mission_winners": return mission_winners;
      default: return null;
    }
  }
}