Edit in JSFiddle

var app = angular.module("App", []);

var MainCtrl = function($scope) {
    $scope.current = ['1', null, '2'];
};

<div ng-app="App">
  <div ng-controller="MainCtrl"> 
      <div ng-repeat="test in current">
          <li>
              {{test}}
              <span ng-if="!test">null</span>
          </li>
      </div>
  </div>
</div>