title: Angular navigation problem with the ngOnInit method of the previous page
body: <p>I have two pages A and B and navigation takes place from page A to page B.<br />
  On page B I inserted a button to go back:</p>
  <pre><code>import { Location } from '@angular/common';
  ...
  this.location.back();  
  </code></pre>
  <p>Navigation works correctly, but I don't want the ngOnInit method in page A to be invoked again when I go back.<br />
  This is the method I use to navigate between the two pages:</p>
  <pre><code>this.router.navigate(['/pages/page-b', item_id]);
  </code></pre>
  <p><strong>UPDATE:</strong></p>
  <p>I would not want the xxx method to be called because it makes database calls which in this case I would like to avoid</p>