CODEWITHSUNDEEP
javascriptangularjsspringfrontendangular-fullstack
Paul Hubert
Paul Hubert

Reputation: 49

Is the @Injectable decorator basically the angular 2 equivalent of @Component or @Autowired in Spring?

Does @Injectable mean

"allow injection of whatever into the class which the decorator is above"

Or

Does it mean "allow me to inject this class (which the decorator is above) into 'wherever' in the application"?

Upvotes: 2

Views: 1936

Answers (1)

Daniel C.
Daniel C.

Reputation: 5758

@Injectable is just a marker that tells to angular engine that the class is available to be created by Injectors. At runtime angular tells to Injectors to read all the @Injectable classes and instantiate them and make them available to be injected to the classes that reference them.

For example lets suppose that there is a service in angular called UserService and you need to use that service in a component called RegistrationComponent. 

@Injectable()
export class UserService {

     saverUser(User user)
     .....
     }

Then in the RegistrationComponent constructor declare an input parameter that reference to UserService, it tells to angular that UserService should be injected to RegistrationComponent, of course previously the @Injectable marker should be declared in UserService

RegistrationComponent.ts

export class RegistrationComponent 

  constructor(private userService: UserService) { }

In the Spring context the @Component plays a similar job than @Injectable of course there are many difference between them in the implementation, but both of them play a similar role. @Component is an annotation that tells to Spring that some specific class has to be considered a candidate for auto-detection and that class can lives in the Spring Container. The components (beans) living in the Spring Container can be injected to other classes.

@Autowired is not the same as @Component. @Autowired means that an specific class member should be provided or injected by Spring DI container.

For more information please see the following links:

Angular Dependency Injection

@Autowired Spring Documentation

@Component Spring Documentation

Upvotes: 3

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