fix JSON to match native browser behavior

Author: mhevery

src/JSON.js

@@ -128,9 +128,9 @@ function toJsonArray(buf, obj, pretty, stack) {
       var childPretty = pretty ? pretty + "  " : false;
       var keys = [];
       for(var k in obj) {
-        if (obj[k] === undefined)
-          continue;
-        keys.push(k);
+        if (obj.hasOwnProperty(k) && obj[k] !== undefined) {
+          keys.push(k);
+        }
       }
       keys.sort();
       for ( var keyIndex = 0; keyIndex < keys.length; keyIndex++) {

test/JsonSpec.js

@@ -78,10 +78,11 @@ describe('json', function(){
     expect(angular.toJson(obj)).toEqual('{"$a":"a"}');
   });
 
-  it('should serialize inherited properties', function() {
+  it('should NOT serialize inherited properties', function() {
+    // This is what native Browser does
     var obj = inherit({p:'p'});
     obj.a = 'a';
-    expect(angular.toJson(obj)).toEqual('{"a":"a","p":"p"}');
+    expect(angular.toJson(obj)).toEqual('{"a":"a"}');
   });
 
   it('should serialize same objects multiple times', function() {