From bf7479678d264ccad809f379878b9da59273941f Mon Sep 17 00:00:00 2001
From: Brandon Dail <brandondail@fb.com>
Date: Mon, 14 Jan 2019 16:35:42 -0800
Subject: [PATCH] Avoid new Set([iterable]) for thenables

Fixes https://github.com/facebook/react/issues/14583

Using `new Set([iterable])` does not work with IE11's non-compliant Set
implementation. By avoiding this pattern we don't need to require a Set
polyfill for IE11
---
 packages/react-reconciler/src/ReactFiberUnwindWork.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/react-reconciler/src/ReactFiberUnwindWork.js b/packages/react-reconciler/src/ReactFiberUnwindWork.js
index 86e2b1a964a..f8c0b050f04 100644
--- a/packages/react-reconciler/src/ReactFiberUnwindWork.js
+++ b/packages/react-reconciler/src/ReactFiberUnwindWork.js
@@ -214,7 +214,8 @@ function throwException(
         // attach another listener to flip the boundary back to its normal state.
         const thenables: Set<Thenable> = (workInProgress.updateQueue: any);
         if (thenables === null) {
-          workInProgress.updateQueue = (new Set([thenable]): any);
+          workInProgress.updateQueue = (new Set(): any);
+          workInProgress.updateQueue.add(thenable);
         } else {
           thenables.add(thenable);
         }