$watchers-count-ng.js

vm.count = function() {
  var root = angular.element(document.getElementsByTagName("body"));

  var watchers = [];

  var f = function(element) {
    angular.forEach(["$scope", "$isolateScope"], function(scopeProperty) {
      if (element.data() && element.data().hasOwnProperty(scopeProperty)) {
        angular.forEach(element.data()[scopeProperty].$$watchers, function(
          watcher
        ) {
          watchers.push(watcher);
        });
      }
    });

    angular.forEach(element.children(), function(childElement) {
      f(angular.element(childElement));
    });
  };

  f(root);

  // Remove duplicate watchers
  var watchersWithoutDuplicates = [];
  angular.forEach(watchers, function(item) {
    if (watchersWithoutDuplicates.indexOf(item) < 0) {
      watchersWithoutDuplicates.push(item);
    }
  });

  $scope.result = watchersWithoutDuplicates.length;
};