From 7b945a9fcecc5f66669fca0b39af8bac5536e6c3 Mon Sep 17 00:00:00 2001
From: Michael Terry <mterry@edx.org>
Date: Thu, 3 Mar 2022 09:48:41 -0500
Subject: [PATCH] fix: guard access to a react ref before using it

This was causing some errors ever since we started using the ref
in an event handler - I'm not entirely sure why the ref stops
being valid, unless it's a lifecycle thing. But anyway, this
seems to stop the error in testing.
---
 src/course-home/outline-tab/LmsHtmlFragment.jsx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/course-home/outline-tab/LmsHtmlFragment.jsx b/src/course-home/outline-tab/LmsHtmlFragment.jsx
index 7ac2d783..d2db4071 100644
--- a/src/course-home/outline-tab/LmsHtmlFragment.jsx
+++ b/src/course-home/outline-tab/LmsHtmlFragment.jsx
@@ -28,7 +28,9 @@ export default function LmsHtmlFragment({
 
   const iframe = useRef(null);
   function resetIframeHeight() {
-    iframe.current.height = iframe.current.contentWindow.document.body.scrollHeight;
+    if (iframe.current) {
+      iframe.current.height = iframe.current.contentWindow.document.body.scrollHeight;
+    }
   }
 
   useEffect(() => {