Avoid "Member not found" error in IE

Explanation, discussion, and similar change as facebook#7343 Addresses facebook#7320
gmp · Aug 12, 2016 · 9560eda · 9560eda
1 parent c8f7215
commit 9560eda
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/renderers/shared/stack/event/SyntheticEvent.js b/src/renderers/shared/stack/event/SyntheticEvent.js
@@ -121,7 +121,7 @@ Object.assign(SyntheticEvent.prototype, {
 
     if (event.preventDefault) {
       event.preventDefault();
-    } else {
+    } else if (typeof event.returnValue !== 'unknown') { // eslint-disable-line valid-typeof
       event.returnValue = false;
     }
     this.isDefaultPrevented = emptyFunction.thatReturnsTrue;