I am trying to retrieve a list of dogs from a database. I want to retrieve the list of dogs as an Observable<Dog[]>. However when I call toArray() or use any other method to try convert the incoming stream to an array I either receive no data when calling the retrieveDogs(dogsId) method. How does one go about retrieving an Observable array instead of just an Observable stream?

    retrieveDogs(dogIds : Array<string>): Observable<Dog[]>{
        return Observable.from(dogIds)
                .map(dogId => this.retrieveDog(dogId)) 
                .flatMap(dogObservable => dogObservable)
                .toArray();
     }

    retrieveDog(dogId : string) : Observable<DogEntity> {
     //afDB -> AngularFireDatabase that returns an observable with the data from the firebase database
        return this.afDB.object(DB_DOGS + DB_DASH + dogId)
                .map(dogObject =>DogEntity.convertObject(dogId,dogObject)
    }