From ce748f9f71fa729ba8bdb13f3378210768369164 Mon Sep 17 00:00:00 2001
From: Leo Horie <leohorie@hotmail.com>
Date: Thu, 26 May 2016 11:30:27 -0400
Subject: [PATCH] check for existence of Promise before doing check against it

---
 mithril.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mithril.js b/mithril.js
index 464e8a5f..01e0794a 100644
--- a/mithril.js
+++ b/mithril.js
@@ -1338,7 +1338,7 @@
 	}
 
 	m.prop = function (store) {
-		if ((store != null && isObject(store) || isFunction(store)) || store instanceof window.Promise &&
+		if ((store != null && isObject(store) || isFunction(store)) || (typeof Promise !== "undefined" && store instanceof Promise) &&
 				isFunction(store.then)) {
 			return propify(store)
 		}