angular - RxJs Observable with WebSocket

Question

My angular application uses a websocket to communicate with the backend.

In my test case I have 2 client components. The Observable timer prints two different client id's as expected.

Each ngOnInit() also prints the id of its client.

NOW for some reason, the subscription of websocketService.observeClient() is called 2 times for each message but this.client.id always prints the value of the second client.

Heres my client component

@Component({
...
})
export class ClientComponent implements OnInit {

  @Input() client: Client;

  constructor(public websocketService: WebsocketService) {
    Observable.timer(1000, 1000).subscribe(() => console.log(this.client.id));
  }

  ngOnInit() {

    console.log(this.client.id);
    this.websocketService.observeClient().subscribe(data => {
      console.log('message', this.client.id);
    });

  }

}

And my websocket Service

@Injectable()
export class WebsocketService {

  private observable: Observable<MessageEvent>;
  private observer: Subject<Message>;

  constructor() {

    const socket = new WebSocket('ws://localhost:9091');

    this.observable = Observable.create(
      (observer: Observer<MessageEvent>) => {
        socket.onmessage = observer.next.bind(observer);
        socket.onerror = observer.error.bind(observer);
        socket.onclose = observer.complete.bind(observer);
        return socket.close.bind(socket);
      }
    );

    this.observer = Subject.create({
      next: (data: Message) => {
        if (socket.readyState === WebSocket.OPEN) {
          socket.send(JSON.stringify(data));
        }
      }
    });

  }

  observeClient(): Observable<MessageEvent> {
    return this.observable;
  }

}

---

Edit

Ok as far as I have read it has to do with the fact that Observables are unicast objects and I have to use a Subject for that but I don't know how to create the Subject.

Answer 1

As of rxjs 5 you can use the built-in websocket feature which creates the subject for you. It also reconnects when you resubscribe to the stream after an error. Please refer to this answer:

https://stackoverflow.com/a/44067972/552203

TLDR:

 let subject = Observable.webSocket('ws://localhost:8081');
 subject
   .retry()
   .subscribe(
      (msg) => console.log('message received: ' + msg),
      (err) => console.log(err),
      () => console.log('complete')
    );
 subject.next(JSON.stringify({ op: 'hello' }));