title: When does angular 2 call onDestroy on a component?
body: <p>I am not able to figure out when does the angular decide to call <em>onDestory</em> event? </p>
  
  <p>When I toggle the component with <code>*ngIF</code> directive, onDestory is not called and the state of the component is maintained as if it is using the same instance of the component? </p>
  
  <p>Can anybody elaborate as to when angular(2) destroys component? And how to achieve newer instance of component when toggling with <code>*ngIf</code>?</p>