Use a own clone function instead of using JSON.parse(JSON.stringify())

This will also clone functions

lib/utils.js

@@ -38,9 +38,36 @@ function print (err, reply) {
 
 var redisErrCode = /^([A-Z]+)\s+(.+)$/;
 
+// Deep clone arbitrary objects with arrays. Can't handle cyclic structures (results in a range error)
+function clone (obj) {
+    if (obj) {
+        var copy;
+        if (obj.constructor === Array) {
+            copy = new Array(obj.length);
+            for (var i = 0; i < obj.length; i++) {
+                copy[i] = clone(obj[i]);
+            }
+            return copy;
+        }
+        if (obj.constructor === Object) {
+            copy = {};
+            for (var elem in obj) {
+                if (!obj.hasOwnProperty(elem)) {
+                    // Do not add non own properties to the cloned object
+                    continue;
+                }
+                copy[elem] = clone(obj[elem]);
+            }
+            return copy;
+        }
+    }
+    return obj;
+}
+
 module.exports = {
     reply_to_strings: replyToStrings,
     reply_to_object: replyToObject,
     print: print,
-    err_code: redisErrCode
+    err_code: redisErrCode,
+    clone: clone
 };