title: how to know which object property changed?
body: <p>I have a map of 10 objects. Each object has 10 properties val1, ..., val10. Now to check of a specific property of a specific object in the map has changed, I would need to write $scope.$watch 100 times. How to watch an entire map/JSobject and know exactly which property has changed?</p>
  
  <pre><code>/*watch individual property*/
              $scope.$watch('map[someid].val1', function(new_val, old_val)
              {
                  //do something
              });
  
      /*watch entire object, how would this help me?*/
              $scope.$watch('map', function(new_val, old_val)
              {
                  //do something
              }, true);
  </code></pre>