title: Change a property if route equals to a certain value, Angular 5
body: <p>I need to change <code>verticalNavType</code> property's value if url is exactly equals to <code>'/admin'</code>. </p>
  
  <p>I try something like this</p>
  
  <pre><code>constructor(
  private router: Router
  ) {
  if (this.router.url === '/admin') {
      this.verticalNavType = 'offcanvas';
  }   
  }
  </code></pre>
  
  <p>But it's change the value even router equals to for example <code>'/admin/company_profile'</code>.
  How can I change the value only for <code>'/admin'</code> ?</p>