Is there any way for this code in the constructor of my service TranslatorService is calling just one time for all application or on demande, and not all time homecomponent is load ????

```
this.translations$ = translationsCollection.snapshotChanges().map(actions => {
      return actions.map(a => {
        ...
      })

```

translation class for my translate retrive from firestore ex:

```
{
  "WELCOME": {
   "FR": "bienvenue",
   "GB": "Welcome"
 }
}

export interface Translation {
    [code: string]: TranslationInfo;

}

export interface TranslationInfo {
    [language: string]: string;
}

```

my core module 

```
import { NgModule } from '@angular/core';
import { AuthService } from './auth.service';
import { AngularFireAuthModule } from 'angularfire2/auth';
import { AngularFirestoreModule } from 'angularfire2/firestore';
import { TranslatorService } from '../services/translator.service';
@NgModule({
imports: [
    AngularFireAuthModule,
    AngularFirestoreModule
],
providers: [AuthService, TranslatorService]
})
export class CoreModule { }

```

injected in appmodule

```
@NgModule({
declarations: [
...

],
imports: [
...
    CoreModule,
...
],
providers: [AuthGuard],
bootstrap: [AppComponent]
})
export class AppModule { }

```

my translator service

```
    @Injectable()
export class TranslatorService {

  translationsCollection: AngularFirestoreCollection<Translation>;
  translations$: Observable<any>;
  public translations: Translation[];

  constructor(private afs: AngularFirestore) {
    var translationsCollection = this.afs.collection("translations");
    this.translations$ = translationsCollection.snapshotChanges().map(actions => {
      return actions.map(a => {
        ...
      })
    });

```

my component 

```
    export class HomeComponent implements OnInit {
translations$: Observable<any>;
constructor(private translator: TranslatorService) { }

ngOnInit() {
    this.translations$ = this.translator.translations$;
}

```

my component view

```
<div *ngFor="let translation of translations$|async">
<pre>{{translation | json}}</pre>
</div>

```