From 4d5f85ed426cfb43dc5e63f915e416a47d76b965 Mon Sep 17 00:00:00 2001
From: Dustin Savery <dsavery@godaddy.com>
Date: Mon, 28 Jan 2019 03:18:46 -0800
Subject: [PATCH] Fixing overscrolling issue on Virtualized List (#23181)

Summary:
Changelog:
----------
[iOS][fixed] Fixed overscroll behavior on iOS virtualized lists (Fixes #18098)
Pull Request resolved: https://github.com/facebook/react-native/pull/23181

Differential Revision: D13838579

Pulled By: cpojer

fbshipit-source-id: 2ec5787218ecca0e01aaf31bfbb7d630cf9f1f09
---
 Libraries/Lists/VirtualizedList.js | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Libraries/Lists/VirtualizedList.js b/Libraries/Lists/VirtualizedList.js
index f6a9c6e2ee7c6e..a14bcde7be8305 100644
--- a/Libraries/Lists/VirtualizedList.js
+++ b/Libraries/Lists/VirtualizedList.js
@@ -330,13 +330,20 @@ class VirtualizedList extends React.PureComponent<Props, State> {
       return;
     }
     const frame = this._getFrameMetricsApprox(index);
-    const offset =
+    const maxScroll =
+      this._scrollMetrics.contentLength - this._scrollMetrics.visibleLength;
+    let offset =
       Math.max(
         0,
         frame.offset -
           (viewPosition || 0) *
             (this._scrollMetrics.visibleLength - frame.length),
       ) - (viewOffset || 0);
+
+    /* Fix for overscrolling */
+    if (offset > maxScroll) {
+      offset = maxScroll;
+    }
     /* $FlowFixMe(>=0.53.0 site=react_native_fb,react_native_oss) This comment
      * suppresses an error when upgrading Flow's support for React. To see the
      * error delete this comment and run Flow. */