AngularJS - orderBy in Ctrl

HTML

<div ng-controller="MyCtrl">
    I have {{friends.length}} friends. They are:
    <ul  ng-repeat="friend in sortedFriends">
      <li>
          <ng-switch on="$first || friend.age != sortedFriends[$index-1].age">
              <div ng-switch-when="true" class="group">Group of {{friend.age}} years old.  Previous: <i>{{sortedFriends[$index-1].age}}</i></div>
          </ng-switch>
          <b>[{{$index + 1}}]</b> {{friend.name}} who is {{friend.age}} years old.
      </li>
    </ul>
  </div>

CSS

body { margin: 4px }
.group { margin-top: 1em; border-bottom: 1px solid #CCC; }
/*.ng-scope { margin: 4px; border: 1px dashed red; }*/

JavaScript

function MyCtrl($scope, orderByFilter) {
    $scope.friends = [{
        name: 'John',
        age: 25},
    {
        name: 'Jimmy',
        age: 25},
    {
        name: 'Mary',
        age: 28},
    {
        name: 'Ed',
        age: 27},
    {
        name: 'Andrew',
        age: 27}];
    $scope.sortedFriends = orderByFilter($scope.friends, '+age');
}