| name | flutter-dependency-injection |
| description | Standards for automated service locator setup using injectable and get_it. Use when configuring dependency injection with injectable and get_it in Flutter. (triggers: **/injection.dart, **/locator.dart, GetIt, injectable, singleton, module, lazySingleton, factory) |
Dependency Injection
Priority: P1 (HIGH)
Automated class dependency management using get_it and injectable.
Structure
core/injection/
├── injection.dart # Initialization & setup
└── modules/ # Third-party dependency modules (Dio, Storage)
Implementation Guidelines
- Automated Registration: Use @injectable annotations; avoid manual registry calls.
- @LazySingleton: Default for repositories, services, and data sources (init on demand).
- Factory Registration: Use @injectable (Factory) for BLoCs to ensure state resets on every new instance/request. Do NOT use
@Singleton() for BLoCs.
- Abstract Injection: Always register implementations as abstract interfaces (as: IService).
- Modules: Use @module for registering third-party instances (e.g., Dio, Hive,
SharedPreferences).
- Constructor Injection: Use mandatory constructor parameters;
injectable resolves them automatically.
- Test Mocks: Swap implementations in
setUp using getIt.unregister() followed by getIt.registerLazySingleton(() => MockService()).
Reference & Examples
For module configuration and initialization templates:
See references/REFERENCE.md.
Anti-Patterns
- ❌
getIt<OrderRepository>() inside widget build() — inject via constructor, not GetIt calls in UI
- ❌
@Singleton() on a BLoC — BLoCs must use @injectable (Factory) so state resets per instance
- ❌ Injecting the concrete class:
OrderRepositoryImpl repo — always inject the abstract interface
- ❌
getIt.registerLazySingleton<X>(() => X()) in production code — use @injectable annotations; manual registration is only for tests
Related Topics
layer-based-clean-architecture | testing
