From 11eb25eaae655861f276789998c653185275df5b Mon Sep 17 00:00:00 2001
From: Daniel Brain <daniel@bluesuncorp.co.uk>
Date: Wed, 2 Jan 2019 10:36:54 +0000
Subject: [PATCH] Extra safety around getting source window from post message

---
 src/drivers/receive/index.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/drivers/receive/index.js b/src/drivers/receive/index.js
index 1f06908c..e7595278 100644
--- a/src/drivers/receive/index.js
+++ b/src/drivers/receive/index.js
@@ -124,11 +124,19 @@ export function messageListener(event : { source : CrossDomainWindowType, origin
 
     // $FlowFixMe
     let messageEvent : MessageEvent = {
-        source: event.source || event.sourceElement,
+        source: event.source || event.sourceElement || event.srcElement,
         origin: event.origin || (event.originalEvent && event.originalEvent.origin),
         data:   event.data
     };
 
+    if (!messageEvent.source) {
+        throw new Error(`Post message did not have source window`);
+    }
+
+    if (!messageEvent.origin) {
+        throw new Error(`Post message did not have origin domain`);
+    }
+
     if (__TEST__) {
         if (needsGlobalMessagingForBrowser() && isSameTopWindow(messageEvent.source, window) === false) {
             return;