addSingleton<T extends Object> static method

void addSingleton<T extends Object>(T instance)

Registers an already existing instance as a Singleton

Useful for pre-configured objects or third-party dependencies initialized asynchronously during app startup (e.g., SharedPreferences). Throws an IonLocatorDuplicateRegistrationException if the type is already registered.

Implementation

static void addSingleton<T extends Object>(T instance) {
  if (_factories.containsKey(T)) {
    throw IonLocatorDuplicateRegistrationException(T);
  }
  _singletons[T] = instance;
  _factories[T] = () => _singletons[T]!;
}