如何在angular js 1中获取ng-repeat项目计数？

<div ng-app="myApp" ng-controller="myCtrl">
  <ul>
    <li ng-repeat="item in items">
      {{$index + 1}}. {{item}}
    </li>
  </ul>
</div>

<script>
  var app = angular.module('myApp', []);
  app.controller('myCtrl', function($scope) {
    $scope.items = ['Item 1', 'Item 2', 'Item 3'];
  });
</script>