title: Angular2 : Should Host listeners be unsubscibed? How does Host Listner work? If I do not have to unsubscribe, When does it get unsubscribed?
body: <pre><code> @HostListener('window:scroll', ['$event'])
    onScroll(event) {
      // Do something
    }
  </code></pre>
  
  <p>I have been listening to scroll events in many components. And I am not unsubscribing. Does it cause a problem.</p>