From 4195e0593b842873ad3e8fc1f7e9eb08af4d395d Mon Sep 17 00:00:00 2001
From: Levi <32551245+LeviWilliams@users.noreply.github.com>
Date: Tue, 3 Feb 2026 13:44:37 -0600
Subject: [PATCH 1/3] Clear stale sizes on data change

---
 src/core/calculateItemsInView.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/core/calculateItemsInView.ts b/src/core/calculateItemsInView.ts
index 8562765f..44d95a71 100644
--- a/src/core/calculateItemsInView.ts
+++ b/src/core/calculateItemsInView.ts
@@ -264,6 +264,16 @@ export function calculateItemsInView(
             indexByKey.clear();
             idCache.length = 0;
             positions.clear();
+            const { sizesKnown } = state;
+            const staleKeys = new Set([...sizesKnown.keys(), ...sizes.keys()]);
+            for (let i = 0; i < data.length; i++) {
+                const id = keyExtractor ? keyExtractor(data[i], i) : String(i);
+                staleKeys.delete(id);
+            }
+            for (const key of staleKeys) {
+                sizesKnown.delete(key);
+                sizes.delete(key);
+            }
         }
 
         // Update all positions upfront so we can assume they're correct

From 5df182d5dc4c5cbd6f6042cf0d0de6a40175a1cc Mon Sep 17 00:00:00 2001
From: Levi <32551245+LeviWilliams@users.noreply.github.com>
Date: Tue, 3 Feb 2026 15:14:51 -0600
Subject: [PATCH 2/3] Don't stringify default id

---
 src/core/calculateItemsInView.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/core/calculateItemsInView.ts b/src/core/calculateItemsInView.ts
index 44d95a71..b58517c7 100644
--- a/src/core/calculateItemsInView.ts
+++ b/src/core/calculateItemsInView.ts
@@ -267,7 +267,8 @@ export function calculateItemsInView(
             const { sizesKnown } = state;
             const staleKeys = new Set([...sizesKnown.keys(), ...sizes.keys()]);
             for (let i = 0; i < data.length; i++) {
-                const id = keyExtractor ? keyExtractor(data[i], i) : String(i);
+                const id = keyExtractor ? keyExtractor(data[i], i) : i;
+                // @ts-expect-error Types will match at runtime
                 staleKeys.delete(id);
             }
             for (const key of staleKeys) {

From 0c4ac3ab295bb214915b7de3b13d82623ba458e8 Mon Sep 17 00:00:00 2001
From: Levi <32551245+LeviWilliams@users.noreply.github.com>
Date: Tue, 3 Feb 2026 16:08:09 -0600
Subject: [PATCH 3/3] Leverage preexisting util

---
 src/core/calculateItemsInView.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/core/calculateItemsInView.ts b/src/core/calculateItemsInView.ts
index b58517c7..ddf408b7 100644
--- a/src/core/calculateItemsInView.ts
+++ b/src/core/calculateItemsInView.ts
@@ -267,8 +267,7 @@ export function calculateItemsInView(
             const { sizesKnown } = state;
             const staleKeys = new Set([...sizesKnown.keys(), ...sizes.keys()]);
             for (let i = 0; i < data.length; i++) {
-                const id = keyExtractor ? keyExtractor(data[i], i) : i;
-                // @ts-expect-error Types will match at runtime
+                const id = getId(state, i);
                 staleKeys.delete(id);
             }
             for (const key of staleKeys) {