title: Concat two observables into one observable so that values get fired on one observable only
body: <p>I want to join two observables of type <code>T[]</code> returned from httpservice.</p>
  
  <p>I tried forkjoin and zip but they return an Observable of type <code>[T[], T[]]</code> and I want to return an object of type <code>T[]</code> as shown in the code below.
  Is there a way to do that in angular 7? </p>
  
  <p>Please help I need this for my work.</p>
  
  <pre class="lang-js prettyprint-override"><code>public getSelectFlux(value): Observable&lt;SelectAutocompleteModel[]&gt; {
    if (!this.isFluxAuto) {
      return forkJoin(this.selectAutoCompleteService.selectedFlux(
        this.getInstance(value, false)), this.selectAutoCompleteService.selectedFlux(this.getInstance(value, true)));
    }
    return this.selectAutoCompleteService.selectedFlux(this.getInstance(value, false));
  }
  
  </code></pre>