refact($anchorScroll): use Array.some for better performance

Author: petebacondarwin

src/ng/anchorScroll.js

@@ -62,14 +62,16 @@ function $AnchorScrollProvider() {
   this.$get = ['$window', '$location', '$rootScope', function($window, $location, $rootScope) {
     var document = $window.document;
 
-    // helper function to get first anchor from a NodeList
-    // can't use filter.filter, as it accepts only instances of Array
-    // and IE can't convert NodeList to an array using [].slice
-    // TODO(vojta): use filter if we change it to accept lists as well
+    // Helper function to get first anchor from a NodeList
+    // (using `Array#some()` instead of `angular#forEach()` since it's more performant
+    //  and working in all supported browsers.)
     function getFirstAnchor(list) {
       var result = null;
-      forEach(list, function(element) {
-        if (!result && nodeName_(element) === 'a') result = element;
+      Array.prototype.some.call(list, function(element) {
+        if (nodeName_(element) === 'a') {
+          result = element;
+          return true;
+        }
       });
       return result;
     }