AngularJS watch DOM change

Question

I have one auto-carousel directive which iterates through the linked element's children.

The children however are not yet loaded in the DOM, because their ng-ifs expressions have not been parsed yet.

How can I make sure the parent directive knows there have been changes to it's DOM tree?

        <ul class="unstyled" auto-carousel>
          <li class="slide" ng-if="name">{{name}}</li>
          ...
          <li class="slide" ng-if="email">{{email}}</li>
        </ul>

I could use $timeout but that feels unreliable. I could also use ng-show instead of ng-if but that does not answer the question and not what I need.

Answer 1

So here's what I ended up doing:

I discovered you could pass a function to $scope.$watch. From there, it's pretty straightforward to return the value of the expression you want to watch for changes. It will work exactly like passing a key string for a property on the scope.

link: function ($scope, $el, $attrs) {
  $scope.$watch(
    function () { return $el[0].childNodes.length; },
    function (newValue, oldValue) {
      if (newValue !== oldValue) {
        // code goes here
      }
    }
  );
}

I am watching childNodes, not children, because the childNodes list holds elements as well as text nodes and comments. This is priceless because Angular uses comment placeholders for directives like ng-repeat, ng-if, ng-switch and ng-include which perform transclusion and alter the DOM, while children only holds elements.