CODEWITHSUNDEEP
angular
TAM
TAM

Reputation: 1741

More than one persistent service instance

In my Angular app, I have two components, Recordings and Participants, which share a common sub component, RecordingList.

I want each of the two components to have a separate instance of the recording list. These instances should also be persistent in the sense that, when the user has visited another part of the app and returns, the lists are still present. So what I need is two instances of the recording list data structure.

There's the problem:

If I provide the RecordingListService that contains that data structure on the global level, it will be persistent, but there will be only one instance. If I provide it at the module level, there will be an instance every time a component is created, which happens quite frequently. What I need is a way to tell the RecordingList component to access one of the two needed instances, depending on whether it is contained in the Recordings or the Participants component.

Upvotes: 1

Views: 60

Answers (2)

joshua miller
joshua miller

Reputation: 1756

Try providing the service in the component.

For example:

@Component({
  selector:    'app-recordings',
  templateUrl: './recordings.component.html',
  providers:  [ RecordingList ]
})

See documentation here: https://angular.io/guide/hierarchical-dependency-injection#providing-services-in-component

Upvotes: 0

Qiqke
Qiqke

Reputation: 486

you can provide the service by 3 ways: in the @Injectable like

@Injectable({
 providedIn: 'root',
})

and will be avaliable for every component because is setted on the root level. second way; 

@NgModule({
  providers: [
  BackendService,
  Logger
 ],
 ...
})

this the service will be avaliable only for that ngModule(you have just one so its okey) and 3th way:

@Component({
  selector:    'app-hero-list',
  templateUrl: './hero-list.component.html',
  providers:  [ HeroService ]
})

i think if you provide it at component level(the shared subcomponent, should work)

Upvotes: 2

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