From dab9e294f9775703a29d61600580e6cb627496a2 Mon Sep 17 00:00:00 2001
From: JulienIzz <julien.izzillo@gmail.com>
Date: Wed, 18 Sep 2024 11:59:53 +0200
Subject: [PATCH] chore: handle undefined index accesses

---
 .../getNumberOfItemsVisibleOnScreen.ts        | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/packages/lib/src/spatial-navigation/components/virtualizedList/helpers/getNumberOfItemsVisibleOnScreen.ts b/packages/lib/src/spatial-navigation/components/virtualizedList/helpers/getNumberOfItemsVisibleOnScreen.ts
index cb9bff03..edb9aaff 100644
--- a/packages/lib/src/spatial-navigation/components/virtualizedList/helpers/getNumberOfItemsVisibleOnScreen.ts
+++ b/packages/lib/src/spatial-navigation/components/virtualizedList/helpers/getNumberOfItemsVisibleOnScreen.ts
@@ -9,17 +9,21 @@ const getMinSizeOfItems = <T>({
     return itemSize;
   }
 
-  let minSize = itemSize(data[0]); // Initialize with the size of the first item
+  let minSize: number | undefined = undefined;
 
-  for (let i = 1; i < data.length; i++) {
-    const currentSize = itemSize(data[i]);
-    if (currentSize < minSize) {
-      minSize = currentSize;
+  for (let i = 0; i < data.length; i++) {
+    const item = data[i];
+    if (item !== undefined) {
+      const currentSize = itemSize(item);
+      if (minSize === undefined || currentSize < minSize) {
+        minSize = currentSize;
+      }
     }
   }
 
   return minSize;
 };
+
 export const getNumberOfItemsVisibleOnScreen = <T>({
   data,
   listSizeInPx,
@@ -30,5 +34,10 @@ export const getNumberOfItemsVisibleOnScreen = <T>({
   itemSize: number | ((item: T) => number);
 }) => {
   const itemSizeToComputeRanges = getMinSizeOfItems({ data, itemSize });
+
+  if (!itemSizeToComputeRanges) {
+    return 0;
+  }
+
   return Math.floor(listSizeInPx / itemSizeToComputeRanges);
 };