title: Angular 4 : How to use await/async within subscribe
body: <p>I can honestly say await/async in angular is really a great stuff, it reduces a lot of braces, improves readability and prevent a lot of human error. However, one thing puzzles me a lot. how can I use await/async inside subscribe.</p>
  
  <p>let's say</p>
  
  <pre><code> @Injectable()
  export class TableCom extends BaseCom {
    public subject = new Subject&lt;any&gt;();
  
  }
  </code></pre>
  
  <p>TableCom is a provider serves as a communicator between a signalr component and a page component. </p>
  
  <p>so inside the page component constructor, it is using the observable subject to receive new data from signalr component as shown below.</p>
  
  <pre><code>constructor(protected nav: NavController,
          protected db: Storage,
          protected alert: AlertController,
          protected order: OrderData,
          protected translate: TranslateService,
          public navParams: NavParams,
          public toastCtrl: ToastController,
          private table_data: TableData,
          private load: LoadingController,
          private http: Http,
          private com_table: TableCom
  
      )
      {
          super(nav, db, alert, order, translate, undefined, false);
          this.previous_page = navParams.get('previous_page');
          this.subscribe_table = this.com_table.Receive().subscribe(res =&gt;
          {
              await this.SaveTableAsync(res.data);
              this.ReadTableAsync();
          });
      }
  </code></pre>
  
  <p>the issue is that the this.ReadTableAsync() basically has to wait this.SaveTableAsync to be finished before starting. await can be achieved here ? thank you in advance !!</p>