title: Wait until two Observables are complete
body: <p>I want to call a method after two Observables have returned values. I did some searching and it seems like <code>forkJoin</code> is what I want, but I can't get it to work. I know both of these Observables are returning values, as I am using the data for each individually elsewhere in the component, so clearly I'm doing something else wrong.</p>
  
  <p>Here is what I tried. I'm using rxjs v6.4.</p>
  
  <pre><code>forkJoin(
    this.store.pipe(select(fromStore.getAppointmentsLoading)),
    this.clientStore.pipe(select(fromClientStore.getClientsLoading)),
  ).subscribe(
    ([res1, res2]) =&gt; {
      console.log('res1', res1);
      console.log('res2', res2);
    },
    err =&gt; console.error(err),
  );
  </code></pre>
  
  <p>Nothing is logging to the console and I am not getting any errors. Again, the Observables I am passing in are definitely returning values.</p>
  
  <p>Am I doing something wrong, or am I taking the wrong approach entirely by using <code>forkJoin</code>?</p>