Count the number of angular watchers

count_ng_watchers.js

(function () {
    var elements = document.getElementsByClassName('ng-scope');
    var watches = [];
    var visited_ids = {};
    for (var i=0; i < elements.length; i++) {
       var scope = angular.element(elements[i]).scope();
       if (scope.$id in visited_ids) 
         continue;
       visited_ids[scope.$id] = true;
       watches.push.apply(watches, scope.$$watchers);
    }
    return watches.length;
})();