From 917ed96ea9637835415a0a7e70e507ae7530b03c Mon Sep 17 00:00:00 2001
From: John Opferkuch <opfertunes@gmail.com>
Date: Fri, 15 Jul 2016 20:24:45 -0700
Subject: [PATCH] Fix for issue 215:
 https://github.com/SteveSanderson/knockout.mapping/issues/215   check that
 lookup key doesn't step on Object.prototype

---
 knockout.mapping.js | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/knockout.mapping.js b/knockout.mapping.js
index 2ac4a3d..96f0d17 100644
--- a/knockout.mapping.js
+++ b/knockout.mapping.js
@@ -792,7 +792,7 @@
 		var findBucket = function(key) {
 			var bucketKey;
 			try {
-				bucketKey = key;//JSON.stringify(key);
+				bucketKey = validatedBucketKey(key);//JSON.stringify(key);
 			}
 			catch (e) {
 				bucketKey = "$$$";
@@ -805,6 +805,20 @@
 			}
 			return bucket;
 		};
+
+		//make sure the key doesn't step on Object.prototype:
+		var validatedBucketKey = function(key)
+        {
+            if ((typeof key === 'string' || key instanceof String) && 
+                Object.prototype.hasOwnProperty(key) )
+            {
+               return "$$"+ key + "$$";
+            }  
+            else
+            {
+                return key;
+            }
+        } 
 		
 		this.save = function (key, value) {
 			findBucket(key).save(key, value);