title: Angular2 rxjs switchMap with inner map subscribtion emitting multiple observables
body: <p>I have a switch map with an inner map function which is returning multiple obersables like so:</p>
  
  <pre><code>  this.fb
      .getUsersGroupsAsObservable(user.uid, 'contacts')
      .switchMap(groups =&gt; {
        return groups.map(group =&gt; this.fb.getJobsbyGroup(group.id));
      })
      .subscribe(res =&gt; {
        console.log(res); // emits Observable {_isScalar: false, source: Observable, operator: MapOperator}
        this.job$ = res;
      });
  });
  </code></pre>
  
  <p>This is running twice correctly and returning two observables like so:</p>
  
  <pre><code>Observable {_isScalar: false, source: Observable, operator: MapOperator}
  Observable {_isScalar: false, source: Observable, operator: MapOperator}
  </code></pre>
  
  <p>Is there any way to return a list of observables (thinking AngularFireList) which I can then render with an async pipe?</p>
  
  <p>Update: @concat helped me to get an answer to this (but for reason the answer was deleted), I updated my code as follows (its now working perfectly):</p>
  
  <pre><code>  this.fb
      .getUsersGroupsAsObservable(user.uid, 'contacts')
      .switchMap(groups =&gt;
        combineLatest(groups.map(group =&gt; this.fb.getJobsbyGroup(group.id))),
      )
      .subscribe(res =&gt; {
        console.log(res);
        this.jobs = [].concat.apply([], res);
      });
  </code></pre>