title: Angular 4 Router: How to not display parameters in the url bar?
body: <p>When I use:</p>
  
  <pre><code>  constructor(router: Router) {
      router.navigate(['page2', 123456789]);
    }
  </code></pre>
  
  <p>I see <code>example.com/page2/123456789</code> in the address bar. Is it possible to hide it? I <strong>don't</strong> want someone to be able to enter <code>example.com/page2</code> so that he/she navigates to this special page. It should only work internally with the command <code>router.navigate(['xy', 'parameter']);</code></p>