registerSingle<T, R extends T> static method

void registerSingle<T, R extends T>(SpotGetter<R> locator, { String? name, })

Registers a singleton that returns the same instance on each resolution.

Singletons are initialized lazily on first access and cached for subsequent requests. Perfect for shared state, services, and managers.

Type Parameters:

• T: The interface or base type to register
• R: The concrete implementation (must extend or implement T)

Parameters:

• locator: Factory function called once to create the singleton. Use get parameter to resolve dependencies.
• name: Optional name qualifier for named instances

Example:

// Simple singleton
Spot.registerSingle<ISettings, Settings>(
  (get) => Settings(),
);

// Named singleton
Spot.registerSingle<Database, ProductionDatabase>(
  (get) => ProductionDatabase(),
  name: 'production',
);

// Singleton with dependencies
Spot.registerSingle<IAuthService, AuthService>(
  (get) => AuthService(
    apiClient: get<IApiClient>(),
    storage: get<IStorage>(),
  ),
);

See also:

• registerFactory for factory registration
• registerAsync for async singleton registration
• dispose to reset and recreate singletons

Implementation

static void registerSingle<T, R extends T>(SpotGetter<R> locator, {String? name}) {
  final key = SpotKey<T>(T, name);

  if (registry.containsKey(key) && logging) {
    log.w('Overriding single: $key with $R');
  }

  registry[key] = SpotService<T>(SpotType.singleton, locator as SpotGetter<T>, R);

  if (logging) log.v('Registered singleton $key -> $R');
}