title: angular 2 - how to hide nav bar in some components
body: <p>I am created nav bar separately in nav.component.html ,how to hide nav bar in some components like login.component.</p>
  
  <blockquote>
    <p>nav.component.html</p>
  </blockquote>
  
  <pre><code>&lt;nav class="navbar navbar-default navbar-fixed-top navClass"&gt;
      &lt;div class="container-fluid"&gt;
          &lt;div class="navbar-header"&gt;
                  &lt;button type="button" class="navbar-toggle collapsed"
                          (click)="toggleState()"&gt;
                  &lt;span class="sr-only"&gt;Toggle navigation&lt;/span&gt;
                  &lt;span class="icon-bar"&gt;&lt;/span&gt;
                  &lt;span class="icon-bar"&gt;&lt;/span&gt;
                  &lt;span class="icon-bar"&gt;&lt;/span&gt;
              &lt;/button&gt;
  
          &lt;/div&gt;
           &lt;div class="collapse navbar-collapse"
                [ngClass]="{ 'in': isIn }"&gt;
            enter code here   &lt;ul class="nav navbar-nav"&gt;
                 &lt;li class="active"&gt;&lt;a href="#"&gt;Home&lt;/a&gt;&lt;/li&gt;
                 &lt;li&gt;&lt;a href="#"&gt;about&lt;/a&gt;&lt;/li&gt;
  
              &lt;/ul&gt;
  
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/nav&gt;
  </code></pre>