title: Node.js/Express - Render error when page not found
body: <p>I have the following controller/route definition in Node.js (using Express and Mongoose). What would be the leanest most appropriate way to handle Error when the user requests a page that does not exist? </p>
  
  <pre><code>  app.get('/page/:pagetitle', function(req, res) {
        Page.findOne({ title: req.params.pagetitle}, function(error, page) {
            res.render('pages/page_show.ejs',
              { locals: {
                  title: 'ClrTouch | ' + page.title,
                  page:page
              }
            });
        });
    });
  </code></pre>
  
  <p>It currently breaks my app. I believe because I'm not doing anything with the error i'm just passing it to the view like a success?</p>
  
  <pre><code>TypeError: Cannot read property 'title' of null
  </code></pre>
  
  <p>Thanks much.</p>