From d3491c8371c289089874eb9da2ae58e7003ae145 Mon Sep 17 00:00:00 2001
From: Damon Bauer <damonbauer@protonmail.com>
Date: Tue, 19 Aug 2025 06:19:17 -0500
Subject: [PATCH 1/2] fix: enhance type definitions

---
 src/index.ts | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index d982ce9..ab60ce5 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,4 @@
-import type { SectionListData } from "react-native";
+import type { DefaultSectionT, SectionListData } from "react-native";
 
 export type GetItemLayoutParams<T> = {
   getItemHeight:
@@ -6,7 +6,7 @@ export type GetItemLayoutParams<T> = {
     | ((item: T, sectionIndex: number, itemIndex: number) => number);
   getItemSeparatorHeight?:
     | number
-    | ((sectionIndex: number, rowIndex: number) => number);
+    | ((sectionIndex: number, itemIndex: number) => number);
   getListHeaderHeight?: number | (() => number);
   getSectionHeaderHeight?: number | ((sectionIndex: number) => number);
   getSectionFooterHeight?: number | ((sectionIndex: number) => number);
@@ -28,16 +28,19 @@ const resolveValue = <T, Args extends unknown[]>(
     : value;
 
 const getItemLayout =
-  <T>({
+  <ItemT, SectionT = DefaultSectionT>({
     getItemHeight,
     getItemSeparatorHeight = 0,
     getSectionHeaderHeight = 0,
     getSectionFooterHeight = 0,
     getSectionSeparatorHeight = 0,
     getListHeaderHeight = 0,
-  }: GetItemLayoutParams<T>) =>
-  (data: SectionListData<T>[] | null, index: number): GetItemLayoutShape => {
-    if (!data || !data.length) {
+  }: GetItemLayoutParams<ItemT>) =>
+  (
+    data: readonly SectionListData<ItemT, SectionT>[] | null,
+    index: number,
+  ): GetItemLayoutShape => {
+    if (!data?.length || index < 0) {
       return { length: 0, offset: 0, index };
     }
 
@@ -119,3 +122,4 @@ const getItemLayout =
   };
 
 export default getItemLayout;
+export type GetItemLayoutFunction = typeof getItemLayout;

From 09ac0a50f464ed3a4b403dfac4c87abc066891ee Mon Sep 17 00:00:00 2001
From: Damon Bauer <damonbauer@protonmail.com>
Date: Tue, 19 Aug 2025 06:26:43 -0500
Subject: [PATCH 2/2] revert conditional check

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 src/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.ts b/src/index.ts
index ab60ce5..34402f1 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -40,7 +40,7 @@ const getItemLayout =
     data: readonly SectionListData<ItemT, SectionT>[] | null,
     index: number,
   ): GetItemLayoutShape => {
-    if (!data?.length || index < 0) {
+    if (!data?.length) {
       return { length: 0, offset: 0, index };
     }