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Injectable

decorator

Decorator that marks a class as available to be provided and injected as a dependency.

Option Description
providedIn?

Determines which injectors will provide the injectable.

See also

Options

Determines which injectors will provide the injectable.

providedIn?: Type<any> | 'root' | 'platform' | 'any' | null

The following options specify that this injectable should be provided in one of the following injectors:

  • 'root' : The application-level injector in most apps.
  • 'platform' : A special singleton platform injector shared by all applications on the page.
  • 'any' : Provides a unique instance in each lazy loaded module while all eagerly loaded modules share one instance.

Usage notes

Marking a class with @Injectable ensures that the compiler will generate the necessary metadata to create the class's dependencies when the class is injected.

The following example shows how a service class is properly marked so that a supporting service can be injected upon creation.

@Injectable()
class UsefulService {
}

@Injectable()
class NeedsService {
  constructor(public service: UsefulService) {}
}

const injector = Injector.create({
  providers:
      [{provide: NeedsService, deps: [UsefulService]}, {provide: UsefulService, deps: []}]
});
expect(injector.get(NeedsService).service instanceof UsefulService).toBe(true);

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Licensed under the Creative Commons Attribution License 4.0.
https://angular.io/api/core/Injectable