From 2fba819c34f38151d4131fe3559c4f231d9c5835 Mon Sep 17 00:00:00 2001
From: David Joy <djoy@edx.org>
Date: Wed, 15 Jan 2020 12:44:30 -0500
Subject: [PATCH] Assume a position of 0 if position is null.

---
 src/learning-sequence/course/SequenceContainer.jsx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/learning-sequence/course/SequenceContainer.jsx b/src/learning-sequence/course/SequenceContainer.jsx
index 1a4e0ea3..b3b88530 100644
--- a/src/learning-sequence/course/SequenceContainer.jsx
+++ b/src/learning-sequence/course/SequenceContainer.jsx
@@ -51,7 +51,8 @@ function SequenceContainer({
 
   useEffect(() => {
     if (loaded && !unitId) {
-      const position = metadata.position - 1;
+      // The position may be null, in which case we'll just assume 0.
+      const position = metadata.position !== null ? metadata.position - 1 : 0;
       const nextUnitId = metadata.items[position].id;
       history.push(`/course/${courseUsageKey}/${sequenceId}/${nextUnitId}`);
     }