Count angular watchers within an element

gistfile1.js

(function (window) {
	var slice = [].slice;
	window.ngWatchCount = function(base) {
		var elems;
		if (base && typeof base !== "string") {
			elems = slice.call(base.querySelectorAll("*"));
			elems.unshift(base);
		} else if (typeof base === "string") {
			elems = slice.call(document.querySelectorAll(base + ", " + base + " *"));
		} else {
			elems = slice.call(document.querySelectorAll("*"));
		}
		return elems.map(function(elem) {
			var data = angular.element(elem).data();
			//if (data.$scope && data.$scope.$$watchers && data.$scope.$$watchers.length) {
			//	elem.setAttribute("angular-watch-count", data.$scope.$$watchers.length);
			//}
			return data.$scope || null;
		}).filter(function(scope) {
			return scope && scope.$$watchers;
		}).reduce(function(tmp, scope) {
			if (tmp.cache[scope.$id]) {
				return tmp;
			}
			tmp.cache[scope.$id] = true;
			tmp.count += scope.$$watchers.length;
			return tmp;
		}, {
			count : 0,
			cache : {}
		}).count;
	};
})(window);

// usage
// ngWatchCount(document.getElementById("foo")) => 200 (passing a dom element)
// ngWatchCount(".some-qsa-query") => 900              (passing a querySelectorAll selector string, selector included)
// ngWatchCount() == ngWatchCount(document) => 1400    (no argument, will find all watches)