From f6f6a3b02d667aa4ba2d5d50cc19208c4462abfa Mon Sep 17 00:00:00 2001
From: Kris Zyp <kriszyp@gmail.com>
Date: Mon, 1 Nov 2021 20:47:49 -0600
Subject: [PATCH] Use a little more robust method of checking instances

---
 lib/validate.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/validate.js b/lib/validate.js
index 8992d6d..cace89e 100644
--- a/lib/validate.js
+++ b/lib/validate.js
@@ -208,7 +208,7 @@ var validate = exports._validate = function(/*Any*/instance,/*Object*/schema,/*O
 			
 			for(var i in objTypeDef){ 
 				if(objTypeDef.hasOwnProperty(i) && i != '__proto__' && i != 'constructor'){
-					var value = instance[i];
+					var value = instance.hasOwnProperty(i) ? instance[i] : undefined;
 					// skip _not_ specified properties
 					if (value === undefined && options.existingOnly) continue;
 					var propDef = objTypeDef[i];