title: Make call to service on route change
body: <p>I am aware that when you navigate to an identical path the component is not reloaded / <code>ngOnInit()</code> is not recalled (makes sense).</p>
  
  <p>I have seen a bunch of SO answers which suggest subscribing to <code>activatedRoute.params</code> and then re-allocating data from a service as required. This is all well and good, but what is the recommended approach if <strong>there is no url param or it does not change?</strong></p>
  
  <pre><code>{ path: 'screen/text/2', component: template.Template_Text_2_Text_Component },
  </code></pre>
  
  <p>In my case, the path represents a templated layout that can be navigated to  consecutively.</p>
  
  <p>So what is the best method to trigger <code>this.courseService.getActiveScreen()</code> on navigate as currently the following does not work as there are no params...</p>
  
  <pre><code>ngOnInit(): void {
      this.subscription = activatedRoute.params.subscribe(
          () =&gt; this.screen = this.courseService.getActiveScreen()
      );
  }
  </code></pre>