title: How to call multiple http requests parallel and handle errors individually
body: <p>I have 4 functions similar to the one below. Right now I'm calling them one at a time on ngOnInit() but I'm looking for a cleaner way to call all 4 functions (GET HTTP Requests) so that they show spinner... all run parallel... and then close spinner and handle any errors. This is for a project using angular 7.</p>
  <pre><code> getCustomers() {
        return this.apiService.getCustomers()
          .subscribe(
            (data: any) =&gt; {
              this.partners = data;
              this.loading = false;
            },
            error =&gt; {
              console.log(error);
              this.loading = false;
            }
          );
    }
  </code></pre>