AngularJS watch DOM change
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.
If you need to watch for any changes deeper in the element's dom, MutationObserver is the way to go :
.directive('myDirective', function() {
return {
...
link: function(scope, element, attrs) {
var observer = new MutationObserver(function(mutations) {
// your code here ...
});
observer.observe(element[0], {
childList: true,
subtree: true
});
}
};
});
I created a directive module for this angular-dom-events
In your case you could
<ul class="unstyled" auto-carousel>
<li class="slide" ng-if="name" dom-on-create="nameCreated()">{{name}}</li>
<li class="slide" ng-if="email" dom-on-destroy="emailDestroyed()">{{email}}</li>
</ul>
Currently only supports dom-on-create
and dom-on-destroy
, but has better performance then the accepted answer because it will only fire once for each dom event, rather than repeatedly check the $watch callback.