Register lazy singleton that depends on async lazy singleton

[haashem]

OK, the title maybe is confusing but here it is the dependency:

UserPreferences --> IPreferences __> Preferences --> SharedPreferences

I have setup this in main function:

get.registerLazySingletonAsync<SharedPreferences>(
      () async => SharedPreferences.getInstance());
  get.registerLazySingleton<IPreferences>(
      () => Preferences(get<SharedPreferences>()));
  get.registerLazySingleton<UserPreferences>(
      () => UserPreferences(get<IPreferences>()));

But when when I try to access getIt<UserPreferences>() get_it complains I tried to access an instance ofSharedPreferences that was not easy yet.

how can I solve this async dependency?

[escamoteur]

use registerSingletonWithDependencies for the two latter ones

[haashem]

Thanks for hint
To achieve synchronous async registration:

get.registerSingletonAsync<SharedPreferences>(
      () => SharedPreferences.getInstance());
  get.registerSingletonWithDependencies<IPreferences>(
      () => Preferences(get<SharedPreferences>()),
      dependsOn: [SharedPreferences]);
  get.registerSingletonWithDependencies<UserPreferences>(
      () => UserPreferences(get<IPreferences>()),
      dependsOn: [IPreferences]);

then later:

void _checkToshowOnboardingPage(BuildContext context) async {
    await getIt.isReady<UserPreferences>();
    final userPreferences = getIt.get<UserPreferences>();
.
.
.

}

so this way I ensure UserPreferences is ready before trying to access it.
wouldn't be nice isReady returns the UserPreferences? so I don't have to call get

[escamoteur]

Great that this worked for you.

1. returning the instance would be an idea but would be a breaking change. Also most of the time I just use allReady() at some place at startup, and I don't check after that with isReady.
2. you can save some key strokes by omitting the get as GetIt is a callable class, like

 final userPreferences = getIt<UserPreferences>();

[haashem]

👍
It took me a hours to understand and debug the issue; I got fooled that I'm accessing synchronous instance. I appreciate if you can update the read me especially in dependsOn section. provide a hint: if you are trying to get a instance depends on async instance you MUST use allReadywith a FutureBuilder or await isReady<T>()to guarantee dependency is ready before accessing it.

Thanks for supporting this great library 😉

[escamoteur]

Ok will make this more clear!