title: How to get specific element and orderby priority in Firebase and Angular
body: <p>I have a firebase reference like this:</p>
  
  <pre><code>$scope.lessons = $firebaseArray(firebase.child('Lessons').orderByChild('courseID').equalTo($state.params.courseID));
  </code></pre>
  
  <p>I'm outputting the lessons like this:</p>
  
  <pre><code>&lt;ul&gt;
          &lt;li class="lesson" ng-if="lesson.moduleID == module.$id" ng-repeat="lesson in lessons" lessonid="{{lesson.$id}}"&gt;
              &lt;lessonedit&gt;&lt;/lessonedit&gt;
          &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>I need to order the lessons by priority, but when I add the orderByPriority() function to the end of the firebase reference it says I can only use one orderBy call.</p>
  
  <p>I tried the filter <code>lesson in lessons | orderByPriority</code> but it says that filter does not exist?</p>