title: backbone.js - using parse without calling fetch
body: <p>On page load I'm bootstrapping my data to my collections via <a href="http://backbonejs.org/#FAQ-bootstrap" rel="nofollow noreferrer">this technique</a>. That works great, but I'm running into an issue where I have sub-models which also need to be cast.</p>
  
  <p>For example, I return a JSON collection called Book, and each book array contains 10-20 models themselves called Pages. If I try and access Pages directly, I get the <code>[object][object]</code> error as Backbone can't figure out what type of object it is.</p>
  
  <p>Previously when I was using <code>fetch</code>, I would get around this by using collections which contained a <code>parse</code> action. In <code>parse</code> I would do something like:</p>
  
  <pre><code>Collection_Books = Backbone.Collection.extend({
      model: Model_Book,
      parse: function (response) {
          response.Pages = new Collection_Pages(response.Pages);
          return response;
      }
  });
  </code></pre>
  
  <p>Now that I'm accessing the data directly and not using <code>fetch</code>, the documentation implies that I no longer have access to the <code>parse</code> method.</p>
  
  <p>If I am not using <code>fetch</code> or calling a server on page load, how can I cast sub-models using the Books > Pages example?</p>