title: Angular 2. Remove @Hostlistener()
body: <p>How can I removed <strong>@Hostlistener()</strong> in Angular 2, like used <strong>removeEventListener</strong> in Native JS?  </p>
  
  <p><strong>Example:</strong> 
  <em>I have many dropDown components in my page. When dropDown opened I want to add handler on document click event and to remove handler when dropDown closed.</em></p>
  
  <p><strong>Native JS:</strong></p>
  
  <pre><code>function handler(){
    //do something
  }
  document.addEventListener('click', handler); // add handler
  document.removeEventListener('click', handler); // remove handler
  </code></pre>
  
  <p><strong>Angular 2:</strong></p>
  
  <pre><code>  @HostListener('document: click') onDocumentClick () {
      // do something
    }
  
    // How can I remove handler?
  </code></pre>