title: popTo does not work in ionic
body: <p>I am using ionic3.</p>
  <p>I develop E-commerce app.</p>
  <p>If User has been Login Goto Shipping Page.</p>
  <p>Then I click Navbar back button, Goto Login Page.</p>
  <p><strong>But I need If user is authenticated Does not goto Login Page.</strong></p>
  <p>Because I Assign a local variable.</p>
  <p>Here is my code.</p>
  <pre><code>&lt;ion-navbar&gt;
      &lt;ion-title&gt;Shipping Address&lt;/ion-title&gt;
      &lt;ion-buttons end&gt;
          &lt;button ion-button  (click)=&quot;goback()&quot; &gt;
            &lt;ion-icon class=&quot;customIcon&quot; name=&quot;arrow-back&quot;&gt;&lt;/ion-icon&gt;
          &lt;/button&gt;
      &lt;/ion-buttons&gt;
    &lt;/ion-navbar&gt;
  
  
  
  goback()
    {
      console.log(&quot;HOBACK&quot;)
      if(this.Page == 'Signin')
      {
        this.navCtrl.popToRoot('CartPage');   
      }
    
    }
  </code></pre>
  <p>Page is a query params value.I just passed the value in nav.push().</p>
  <p>My ques</p>
  <p><strong>popToRoot</strong> Does not work why?</p>
  <p>Its also goto previous page(Backhistory).</p>