From 5c7f5d31a40baceb588c8c6e9f8fa00f676bb314 Mon Sep 17 00:00:00 2001
From: Raashish Aggarwal <94279692+raashish1601@users.noreply.github.com>
Date: Sat, 30 May 2026 17:20:55 +0530
Subject: [PATCH] Fix preact infinite query pageParam result typing

---
 .../src/__tests__/useInfiniteQuery.test-d.tsx |  6 ++--
 packages/preact-query/src/useInfiniteQuery.ts | 28 +++++++++++++++++--
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/packages/preact-query/src/__tests__/useInfiniteQuery.test-d.tsx b/packages/preact-query/src/__tests__/useInfiniteQuery.test-d.tsx
index b11002c9e2c..286405bb08b 100644
--- a/packages/preact-query/src/__tests__/useInfiniteQuery.test-d.tsx
+++ b/packages/preact-query/src/__tests__/useInfiniteQuery.test-d.tsx
@@ -61,9 +61,8 @@ describe('select', () => {
       getNextPageParam: () => undefined,
     })
 
-    // TODO: Order of generics prevents pageParams to be typed correctly. Using `unknown` for now
     expectTypeOf(infiniteQuery.data).toEqualTypeOf<
-      InfiniteData<number, unknown> | undefined
+      InfiniteData<number, number> | undefined
     >()
   })
 
@@ -113,9 +112,8 @@ describe('getNextPageParam / getPreviousPageParam', () => {
       },
     })
 
-    // TODO: Order of generics prevents pageParams to be typed correctly. Using `unknown` for now
     expectTypeOf(infiniteQuery.data).toEqualTypeOf<
-      InfiniteData<string, unknown> | undefined
+      InfiniteData<string, number> | undefined
     >()
   })
 })
diff --git a/packages/preact-query/src/useInfiniteQuery.ts b/packages/preact-query/src/useInfiniteQuery.ts
index f78c14a2375..d475ba987fc 100644
--- a/packages/preact-query/src/useInfiniteQuery.ts
+++ b/packages/preact-query/src/useInfiniteQuery.ts
@@ -18,6 +18,19 @@ import type {
 } from './types'
 import { useBaseQuery } from './useBaseQuery'
 
+type IsUnknown<T> = unknown extends T
+  ? [T] extends [never]
+    ? false
+    : true
+  : false
+
+type ResolvePageParamData<TQueryFnData, TData, TPageParam> =
+  TData extends InfiniteData<TQueryFnData, infer TDataPageParam>
+    ? IsUnknown<TDataPageParam> extends true
+      ? InfiniteData<TQueryFnData, TPageParam>
+      : TData
+    : TData
+
 export function useInfiniteQuery<
   TQueryFnData,
   TError = DefaultError,
@@ -33,7 +46,10 @@ export function useInfiniteQuery<
     TPageParam
   >,
   queryClient?: QueryClient,
-): DefinedUseInfiniteQueryResult<TData, TError>
+): DefinedUseInfiniteQueryResult<
+  ResolvePageParamData<TQueryFnData, TData, TPageParam>,
+  TError
+>
 
 export function useInfiniteQuery<
   TQueryFnData,
@@ -50,7 +66,10 @@ export function useInfiniteQuery<
     TPageParam
   >,
   queryClient?: QueryClient,
-): UseInfiniteQueryResult<TData, TError>
+): UseInfiniteQueryResult<
+  ResolvePageParamData<TQueryFnData, TData, TPageParam>,
+  TError
+>
 
 export function useInfiniteQuery<
   TQueryFnData,
@@ -67,7 +86,10 @@ export function useInfiniteQuery<
     TPageParam
   >,
   queryClient?: QueryClient,
-): UseInfiniteQueryResult<TData, TError>
+): UseInfiniteQueryResult<
+  ResolvePageParamData<TQueryFnData, TData, TPageParam>,
+  TError
+>
 
 export function useInfiniteQuery(
   options: UseInfiniteQueryOptions,