title: Does Passport's logout function remove the cookie? If not, how does it work?
body: <p>From the <a href="http://passportjs.org/docs/logout" rel="nofollow noreferrer">docs</a>:</p>
  <blockquote>
  <p>Passport exposes a logout() function on req (also aliased as logOut())
  that can be called from any route handler which needs to terminate a
  login session. Invoking logout() will remove the req.user property and
  clear the login session (if any).</p>
  <pre><code>app.get('/logout', function(req, res){   req.logout();  
  res.redirect('/'); });
  </code></pre>
  </blockquote>
  <p>From reading this and testing myself, it doesn't seem that <code>logout</code> removes the cookie from the client. From what I understand, when the client makes a request, it sends along it's cookie, which Passport deserializes and transforms into <code>req.user</code>.</p>
  <p>Assuming that <code>logout</code> doesn't remove the cookie and that Passport uses the cookie to determine whether or not the user is logged in, how does the <code>logout</code> function
  actually log the user out?</p>