From 5ad1b3d0c62ca49ed10da85989e692196502fd3d Mon Sep 17 00:00:00 2001
From: clean99 <53188310+clean99@users.noreply.github.com>
Date: Sat, 31 Oct 2026 17:56:25 +0800
Subject: [PATCH] fix(svelte-virtual): preserve options when resubscribing

---
 .changeset/quick-lists-return.md            |  5 ++++
 packages/svelte-virtual/src/index.ts        |  2 +-
 packages/svelte-virtual/tests/index.test.ts | 33 +++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/quick-lists-return.md

diff --git a/.changeset/quick-lists-return.md b/.changeset/quick-lists-return.md
new file mode 100644
index 000000000..0fef67600
--- /dev/null
+++ b/.changeset/quick-lists-return.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/svelte-virtual': patch
+---
+
+Preserve updated virtualizer options when a Svelte store is resubscribed.
diff --git a/packages/svelte-virtual/src/index.ts b/packages/svelte-virtual/src/index.ts
index 18b1a62f0..49eb96cef 100644
--- a/packages/svelte-virtual/src/index.ts
+++ b/packages/svelte-virtual/src/index.ts
@@ -63,7 +63,7 @@ function createVirtualizerBase<
   }
 
   virtualizerWritable = writable(virtualizer, () => {
-    setOptions(initialOptions)
+    setOptions({})
     return virtualizer._didMount()
   })
 
diff --git a/packages/svelte-virtual/tests/index.test.ts b/packages/svelte-virtual/tests/index.test.ts
index 91ebc4259..b0de1eb78 100644
--- a/packages/svelte-virtual/tests/index.test.ts
+++ b/packages/svelte-virtual/tests/index.test.ts
@@ -95,6 +95,39 @@ describe.each([
     }
   })
 
+  test('preserves updated options when the store is resubscribed', () => {
+    const onChange = vi.fn()
+    const nextOnChange = vi.fn()
+    const store = create({
+      count: 100,
+      estimateSize: () => 40,
+      getScrollElement: () => null,
+      onChange,
+    })
+    const unsubscribe = store.subscribe(() => {})
+    const virtualizer = get<TestVirtualizer>(store)
+    virtualizer.setOptions({ count: 110, onChange: nextOnChange })
+    unsubscribe()
+
+    const subscriber = vi.fn()
+    const resubscribe = store.subscribe(subscriber)
+
+    try {
+      expect(virtualizer.options.count).toBe(110)
+      expect(virtualizer.getTotalSize()).toBe(4400)
+      onChange.mockClear()
+      nextOnChange.mockClear()
+      subscriber.mockClear()
+      virtualizer.measure()
+
+      expect(onChange).not.toHaveBeenCalled()
+      expect(nextOnChange).toHaveBeenCalledExactlyOnceWith(virtualizer, false)
+      expect(subscriber).toHaveBeenCalledExactlyOnceWith(virtualizer)
+    } finally {
+      resubscribe()
+    }
+  })
+
   test('updates the store when no onChange was supplied', () => {
     const subscriber = vi.fn()
     const store = create({