Angular unique select

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.6/angular.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/angular-ui/0.4.0/angular-ui.min.js"></script>
<div ng-controller="myAppList">
<div>
  <ul>
    <li ng-repeat="x in myArr | unique:id">
      {{ x.campus }}
    </li>
  </ul>
</div>
</div>

JavaScript

var myApp = angular.module('myApp', ['ui.directives','ui.filters']);

myApp.controller('myAppList', function myAppList($scope) {
	$scope.myArr  = [{id: "1", campus: "c1"}, {id: "1", campus: "c1"}, {id: "2", campus: "c2"}, {id: "2", campus: "c2"}];

});