From f3a2dc252edadd360b28b653cde082e066e478be Mon Sep 17 00:00:00 2001
From: Sebastian Markbage <sema@fb.com>
Date: Fri, 2 Sep 2016 17:23:09 -0700
Subject: [PATCH] Check for truthiness of alternate

This is unfortunate since we agreed on using the `null | Fiber`
convention instead of `?Fiber` but haven't upgraded yet and this
is the pattern I've been using everywhere else so far.
---
 src/renderers/shared/fiber/ReactFiberBeginWork.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/renderers/shared/fiber/ReactFiberBeginWork.js b/src/renderers/shared/fiber/ReactFiberBeginWork.js
index cab153c112..80b22b0dd5 100644
--- a/src/renderers/shared/fiber/ReactFiberBeginWork.js
+++ b/src/renderers/shared/fiber/ReactFiberBeginWork.js
@@ -121,7 +121,7 @@ module.exports = function<T, P, I, C>(config : HostConfig<T, P, I, C>, getSchedu
     fiber.updateQueue = updateQueue;
     // Schedule update on the alternate as well, since we don't know which tree
     // is current.
-    if (fiber.alternate !== null) {
+    if (fiber.alternate) {
       fiber.alternate.updateQueue = updateQueue;
     }
     while (true) {
@@ -129,7 +129,7 @@ module.exports = function<T, P, I, C>(config : HostConfig<T, P, I, C>, getSchedu
           fiber.pendingWorkPriority >= priorityLevel) {
         fiber.pendingWorkPriority = priorityLevel;
       }
-      if (fiber.alternate !== null) {
+      if (fiber.alternate) {
         if (fiber.alternate.pendingWorkPriority === NoWork ||
             fiber.alternate.pendingWorkPriority >= priorityLevel) {
           fiber.alternate.pendingWorkPriority = priorityLevel;