title: Angular orderBy object possible?
body: <p>I have a JSON object representing calendar dates. These are added through a CMS and I'd like to be able to filter them based on date. My schema set-up has made this more difficult than I thought. Is it possible to orderBy the day value in this JSON object or is there a filter workaround?</p>
  
  <p>Here is my JSON object:</p>
  
  <pre><code>{
  "_id" : ObjectId("53f252537d343a9ad862866c"),
  "year" : {
      "December" : [],
      "November" : [],
      "October" : [],
      "September" : [],
      "August" : [],
      "July" : [ 
          {
              "day" : "21",
              "title" : "Event Title",
              "summary" : "Event Summary",
              "description" : "oEvent Description",
              "_id" : ObjectId("53f252537d343a9ad862866d")
          }
      ],
      "June" : [],
      "May" : [],
      "April" : [],
      "March" : [],
      "February" : [],
      "January" : []
  },
  "__v" : 0
  }
  </code></pre>
  
  <p>Here is my view which already uses a custom filter to filter by month. The orderBy is not functioning but I've left it in as a placeholder to show where I'd like to set the functionality.</p>
  
  <pre><code>&lt;div class="calDynamic" data-ng-repeat="n in [] | range:100"&gt;
  &lt;div ng-repeat="cal in calendar[n].year | filterKey:month"&gt;
    &lt;div ng-if="cal != '' "&gt;
      &lt;div class="calendar"&gt;
  
  
      &lt;div ng-repeat="item in cal | orderBy: 'key.day' "&gt;
  
          &lt;a href="/events/{{item.day}}"&gt;
            &lt;article class="eventslist"&gt;
             &lt;div class="numberedDate"&gt;
                 &lt;h3&gt;{{item.day}}&lt;/h3&gt;
              &lt;/div&gt;
              &lt;div class="calInfo"&gt;
                 &lt;h5&gt;{{item.title}}&lt;/h5&gt;
                 &lt;p&gt;{{item.summary}}&amp;nbsp;&lt;a&gt;more&lt;/a&gt;&lt;/p&gt;
              &lt;/div&gt;
             &lt;/article&gt;
  
  
        &lt;/div&gt;&lt;!-- ng-repeat val,key --&gt;
  &lt;/div&gt;&lt;!-- calendar --&gt;
  &lt;/div&gt;&lt;!-- ng-if cal --&gt;
  &lt;/div&gt;&lt;!-- ng-repeat cal --&gt;
  &lt;/div&gt;&lt;!-- calDynamic --&gt;
  </code></pre>