Count amount of watchers in angularjs

watchercount.js

function getScopes(root) {
	var scopes = []
	function traverse(scope) {
		scopes.push(scope)
		if (scope.$$nextSibling)
			traverse(scope.$$nextSibling)
		if (scope.$$childHead)
			traverse(scope.$$childHead)
	}
	traverse(root)
	return scopes
}
var rootScope = angular.element(document.querySelectorAll('[ng-app]')).scope()
var scopes = getScopes(rootScope)
var watcherLists = scopes.map(s => s.$$watchers)
_.uniq(_.flatten(watcherLists)).length