From d81c67b6cf02b77611834b3064ad03c5388dae10 Mon Sep 17 00:00:00 2001
From: Janic Duplessis <janicduplessis@gmail.com>
Date: Thu, 7 Dec 2023 17:36:53 -0500
Subject: [PATCH] Fix last spacer constrain logic

---
 .../virtualized-lists/Lists/VirtualizedList.js   | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/packages/virtualized-lists/Lists/VirtualizedList.js b/packages/virtualized-lists/Lists/VirtualizedList.js
index 4efaf669e3d875..33e84cd66d833b 100644
--- a/packages/virtualized-lists/Lists/VirtualizedList.js
+++ b/packages/virtualized-lists/Lists/VirtualizedList.js
@@ -90,19 +90,6 @@ type State = {
   pendingScrollUpdateCount: number,
 };
 
-function findLastWhere<T>(
-  arr: $ReadOnlyArray<T>,
-  predicate: (element: T) => boolean,
-): T | null {
-  for (let i = arr.length - 1; i >= 0; i--) {
-    if (predicate(arr[i])) {
-      return arr[i];
-    }
-  }
-
-  return null;
-}
-
 function getScrollingThreshold(threshold: number, visibleLength: number) {
   return (threshold * visibleLength) / 2;
 }
@@ -987,7 +974,8 @@ class VirtualizedList extends StateSafePureComponent<Props, State> {
       const spacerKey = this._getSpacerKey(!horizontal);
 
       const renderRegions = this.state.renderMask.enumerateRegions();
-      const lastSpacer = findLastWhere(renderRegions, r => r.isSpacer);
+      const lastRegion = renderRegions[renderRegions.length - 1];
+      const lastSpacer = lastRegion?.isSpacer ? lastRegion : null;
 
       for (const section of renderRegions) {
         if (section.isSpacer) {