AngularJS Example

HTML

<div ng-app="">
  <div ng-controller="Ctrl1">
      <div ng-show="isEmpty(sources)">
          EMPTY SOURCES
      </div>
      <div ng-repeat="source in sources">
          {{source.id}}
      </div>
      <button ng-click="cleanSources()">clean</button>
  </div>
</div>

CSS

</style> <!-- Ugly Hack due to jsFiddle issue: http://goo.gl/BUfGZ --> 
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.0.3/angular.min.js"></script>
<style>
.ng-invalid { border: 1px solid red; }

JavaScript

function Ctrl1($scope) {
    $scope.sources = {source1:{id:"source1"},source2:{id:"source2"}};
    
    $scope.cleanSources = function(){
        $scope.sources = {};   
        console.log($scope.sources);                            
    };
    
    $scope.isEmpty = function (obj) {
        return angular.equals({},obj); 
    };
}