From ff006451ad792ed26793691402bf7b5f813205f7 Mon Sep 17 00:00:00 2001
From: Nicolas Gallagher <necolas@fb.com>
Date: Thu, 5 Sep 2019 11:36:31 -0700
Subject: [PATCH] [react-events] Fix isTargetWithinNode type (#16671)

isTargetWithinNode passes the childTarget to getClosestInstanceFromNode which
does not account for a null value of 'node'.
---
 .../src/events/DOMEventResponderSystem.js     |  2 +-
 packages/react-events/src/dom/Tap.js          | 22 ++++++++-----------
 packages/shared/ReactDOMTypes.js              |  2 +-
 3 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/packages/react-dom/src/events/DOMEventResponderSystem.js b/packages/react-dom/src/events/DOMEventResponderSystem.js
index 5941ffdfdff3..d7037122960d 100644
--- a/packages/react-dom/src/events/DOMEventResponderSystem.js
+++ b/packages/react-dom/src/events/DOMEventResponderSystem.js
@@ -158,7 +158,7 @@ const eventResponderContext: ReactDOMResponderContext = {
     return false;
   },
   isTargetWithinNode(
-    childTarget: null | Element | Document,
+    childTarget: Element | Document,
     parentTarget: Element | Document,
   ): boolean {
     validateResponderContext();
diff --git a/packages/react-events/src/dom/Tap.js b/packages/react-events/src/dom/Tap.js
index 250cec367aca..fe5ce0d91e65 100644
--- a/packages/react-events/src/dom/Tap.js
+++ b/packages/react-events/src/dom/Tap.js
@@ -321,22 +321,17 @@ function getHitTarget(
   context: ReactDOMResponderContext,
   state: TapState,
 ): null | Element | Document {
-  if (hasPointerEvents) {
-    return event.target;
-  } else {
-    if (event.pointerType === 'touch') {
-      const doc = context.getActiveDocument();
-      const nativeEvent: any = event.nativeEvent;
-      const touch = getTouchById(nativeEvent, state.activePointerId);
-      if (touch != null) {
-        return doc.elementFromPoint(touch.clientX, touch.clientY);
-      } else {
-        return null;
-      }
+  if (!hasPointerEvents && event.pointerType === 'touch') {
+    const doc = context.getActiveDocument();
+    const nativeEvent: any = event.nativeEvent;
+    const touch = getTouchById(nativeEvent, state.activePointerId);
+    if (touch != null) {
+      return doc.elementFromPoint(touch.clientX, touch.clientY);
     } else {
-      return event.target;
+      return null;
     }
   }
+  return event.target;
 }
 
 function isActivePointer(
@@ -617,6 +612,7 @@ const responderImpl = {
       case 'scroll': {
         if (
           state.isActive &&
+          state.responderTarget != null &&
           // We ignore incoming scroll events when using mouse events
           state.pointerType !== 'mouse' &&
           // If the scroll target is the document or if the pointer target
diff --git a/packages/shared/ReactDOMTypes.js b/packages/shared/ReactDOMTypes.js
index 5ad24bdd02be..53bbb3384b14 100644
--- a/packages/shared/ReactDOMTypes.js
+++ b/packages/shared/ReactDOMTypes.js
@@ -55,7 +55,7 @@ export type ReactDOMResponderContext = {
     eventPriority: EventPriority,
   ) => void,
   isTargetWithinNode: (
-    childTarget: null | Element | Document,
+    childTarget: Element | Document,
     parentTarget: Element | Document,
   ) => boolean,
   isTargetWithinResponder: (null | Element | Document) => boolean,