如何防止每次模型更改时触发ng-repeat（涉及Firebase / angularFire）

Question

I am building the DOM using data synced/fetched from Firebase with angularFire. Every DOM element is built with this simple directive:

angular.module('App')
  .directive('acmsElement', function () {
    return {
      template: '<div ng-transclude></div> ',
      restrict: 'E',
      scope: {elem: '='},
      transclude: true,
      replace: true,
      link: function postLink(scope, element, attrs) {
        var el = angular.element(scope.elem.tag);
        if(scope.elem.content){
          el.text(scope.elem.content);
        }
        if(scope.elem.attributes) {
          el.attr(scope.elem.attributes);
        }
        element.append(el);
      }
    };
  });

and all elements are rendered on the website sequentially using ng-repeat and every element/model is made editable with textarea:

<div ng-repeat="el in elems">
  <acms-element elem="el">
    <textarea style="width: 100%" ng-model="el.content"></textarea>
  </acms-element>
</div>

In the Firebase the nodes are stored as an array, so it is straight forward to display them in the right order using ng-repeat. The problem starts when I try to edit any model bound to a textarea above, the ng-repeats its work on every keystroke. This causes that the focus on the textarea is lost, the page flickers as it is rendered, and most annoyingly, I can input only one character at a time before the page is re-generated. Not sure how to tackle the problem.
Thank you for your time,
Jared

Answer 1

I had a similar issue here: hanging-model-value-in-one-controller-triggers-model-update-in-others .

Every time a model object is changed the digest cycle is called on the $rootScope which will update all the scopes.

A workaround would be to have two separate model variables for Firebase and actual elements so the changes in your textarea will not call the Firebase. Then have a $timeout() function to "sync" (going through properties recursively and update/delete them only if they are changed) those two model objects in the background.