fix(lit-query): add DataTag to the queryKey returned by infiniteQueryOptions

.changeset/wise-doors-shout.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/lit-query': patch
+---
+
+Brand the `queryKey` returned by `infiniteQueryOptions` with `DataTag` so `getQueryData` and `setQueryData` infer `InfiniteData` instead of `unknown`.

packages/lit-query/src/infiniteQueryOptions.ts

@@ -1,15 +1,17 @@
 import type {
+  DataTag,
   DefaultError,
   InfiniteData,
   InfiniteQueryObserverOptions,
   QueryKey,
 } from '@tanstack/query-core'
 
 /**
- * Preserves and types infinite query options for reuse across Lit Query APIs.
+ * Brands infinite query options so the `queryKey` carries the infinite query
+ * data and error types across TanStack Query APIs.
  *
- * @param options - Infinite query options to preserve.
- * @returns The same options object.
+ * @param options - Infinite query options to preserve and brand.
+ * @returns The same options object with a typed `queryKey`.
  *
  * @example
  * ```ts
@@ -43,6 +45,10 @@ export function infiniteQueryOptions<
   TData,
   TQueryKey,
   TPageParam
-> {
+> & {
+  queryKey: DataTag<TQueryKey, InfiniteData<TQueryFnData>, TError>
+}
+
+export function infiniteQueryOptions(options: unknown) {
   return options
 }

packages/lit-query/src/tests/type-inference.test.ts

@@ -2,6 +2,7 @@ import {
   dataTagSymbol,
   QueryClient,
   type DefinedQueryObserverResult,
+  type InfiniteData,
   type QueryObserverResult,
 } from '@tanstack/query-core'
 import { describe, expectTypeOf, it } from 'vitest'
@@ -206,5 +207,26 @@ describe('type inference', () => {
     expectTypeOf(infinite().data?.pages).toEqualTypeOf<
       Array<{ page: number }> | undefined
     >()
+
+    const infiniteQueryOpts = infiniteQueryOptions({
+      queryKey: ['type-inference', 'infinite-query-options'] as const,
+      initialPageParam: 0,
+      queryFn: async () => ({ page: 3 }),
+      getNextPageParam: (lastPage) => lastPage.page + 1,
+    })
+    expectTypeOf(infiniteQueryOpts.queryKey[dataTagSymbol]).toEqualTypeOf<
+      InfiniteData<{ page: number }>
+    >()
+    const cachedPages = client.getQueryData(infiniteQueryOpts.queryKey)
+    expectTypeOf(cachedPages).toEqualTypeOf<
+      InfiniteData<{ page: number }> | undefined
+    >()
+    const updatedPages = client.setQueryData(infiniteQueryOpts.queryKey, {
+      pages: [{ page: 4 }],
+      pageParams: [0],
+    })
+    expectTypeOf(updatedPages).toEqualTypeOf<
+      InfiniteData<{ page: number }> | undefined
+    >()
   })
 })