fix: dont write to elementType if it is not defined, fixes #1357

gaearon · Nov 2, 2019 · 1072303 · 1072303
1 parent fbc890a
commit 1072303
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/src/internal/getReactStack.js b/src/internal/getReactStack.js
@@ -42,7 +42,10 @@ const markUpdate = ({ fiber }) => {
   if (fiber.alternate) {
     fiber.alternate.expirationTime = 1;
     fiber.alternate.type = fiber.type;
-    fiber.alternate.elementType = fiber.elementType;
+    // elementType might not exists in older react versions
+    if ('elementType' in fiber.alternate) {
+      fiber.alternate.elementType = fiber.elementType;
+    }
   }
 
   if (fiber.memoizedProps && typeof fiber.memoizedProps === 'object') {