title: combining results from multiple rxjs observables
body: <p>I have an autocomplete input which, as the user types, fetches data from multiple endpoints, such as:</p>
  
  <pre><code>//service call to fetch data and return as single observable
  getAutocompleteSuggestions() {
      const subs$ = [
          this.http.get(endpoint1),
          this.http.get(endpoint2),
          this.http.get(endpoint3)
      ];
  
      return Observable.forkJoin(...subs$);
  }
  </code></pre>
  
  <p>Each of these endpoints returns data of the form:</p>
  
  <pre><code>{ data: [], status: xyz }
  </code></pre>
  
  <p>I would like to use switchmap as I want to only show results from the final call, and have tried the following:</p>
  
  <pre><code>   this.getAutocompleteSuggestions(query)
            .switchMap(res =&gt; {
               return res.data;
             })
            .subscribe((results: any) =&gt; {
              this.results = results;
            });
  </code></pre>
  
  <p>But the 'res' in the switchmap is an array, any idea how results can contain a single array containing the data from the response of any number of observables?</p>