AngularJS $watch array.

HTML

<div ng-app="">
  <div ng-controller="appCtrl">
     <ul>
        <li ng-repeat="item in items">
           <a href="" ng-init="class=['one', 'two', 'three','sdfsd'];" ng-click="item.num=item.num+1" ng-class="class[item.num%class.length]">{{class[item.num%class.length]}}</a>
         </li>
      </ul>
    </div>
  </div>
</div>

JavaScript

angular.module('app', ['ngResource'])

function appCtrl($scope, $log) {
        $scope.items = [{num:0},{num:1},{num:2}];
        $scope.$watch('items', function(newValue, oldValue) { 
            console.log(newValue)
        }, true);
}