/flutter-dependency-injection

name: flutter-dependency-injection
description: Configure service locator setup using injectable and get_it in Flutter. Use when wiring dependency injection with get_it or injectable.
metadata:
  triggers:
    files:
    - '**/injection.dart'
    - '**/locator.dart'
    keywords:
    - GetIt
    - injectable
    - singleton
    - module
    - lazySingleton
    - factory

Dependency Injection

**Priority: P1 (HIGH)**

Structure

core/injection/
├── injection.dart  # Initialization & setup
└── modules/        # Third-party dependency modules (Dio, Storage)

Implementation Workflow

1. **Annotate classes** — Use `@injectable` annotations; avoid manual registry calls. 2. **Choose scope** — Default to `@LazySingleton` for repositories, services, and data sources (init on demand). 3. **Register BLoCs as factories** — Use `@injectable` (Factory) for BLoCs to ensure state resets per instance. Never use `@Singleton()` for BLoCs. 4. **Inject abstractions** — Always register implementations as abstract interfaces (`as: IService`). 5. **Register third-party deps** — Use `@module` for external instances (Dio, Hive, SharedPreferences). 6. **Prefer constructor injection** — Use mandatory constructor parameters; `injectable` resolves them automatically.

Registration & Test Mock Examples

See [implementation examples](references/implementation.md) for module registration and test mock swap patterns.

Reference & Examples

For module configuration and initialization templates: See [references/REFERENCE.md](references/REFERENCE.md).

Anti-Patterns

• **No Inline `getIt` Calls**: Inject via constructor instead of calling GetIt in UI `build()`
• **No `@Singleton` BLoCs**: Always use `@injectable` (Factory) to ensure state resets
• **No Concrete Class Injection**: Always inject abstract interface (e.g., `IOrderRepository`)
• **No Manual Registration**: Use `@injectable` annotations instead of manual `getIt.register` calls in production code

Related Topics

layer-based-clean-architecture | testing

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

• Dependency Injection
• abstract interface

Remediation anchors

• Remediation anchors: factory registration, fresh CartBloc instance