refactor(angular.toJson): use charAt instead of regexp

just-boris · petebacondarwin · commit 301647bf1b6d · 2013-09-23T11:16:33.000+01:00
Provides a performance improvement when serializing to JSON strings. Closes angular#4093
diff --git a/src/Angular.js b/src/Angular.js
@@ -758,7 +758,7 @@ function bind(self, fn) {
 function toJsonReplacer(key, value) {
   var val = value;
 
-  if (/^\$+/.test(key)) {
+  if (typeof key === 'string' && key.charAt(0) === '$') {
     val = undefined;
   } else if (isWindow(value)) {
     val = '$WINDOW';
