Infer Return Type for select from useInfiniteQuery

.changeset/seven-monkeys-fetch.md

@@ -0,0 +1,5 @@
+---
+"openapi-react-query": minor
+---
+
+[#2169](https://github.com/openapi-ts/openapi-typescript/pull/2169): Infer returned `data` type from `select` option when used with the `useInfiniteQuery` method.

docs/.vitepress/en.ts

@@ -80,6 +80,10 @@ export default defineConfig({
               text: "useSuspenseQuery",
               link: "/use-suspense-query",
             },
+            {
+              text: "useInfiniteQuery",
+              link: "/use-infinite-query",
+            },
             {
               text: "queryOptions",
               link: "/query-options",

docs/openapi-react-query/use-infinite-query.md

@@ -105,6 +105,7 @@ const query = $api.useInfiniteQuery(
   - Only required if the OpenApi schema requires parameters.
   - The options `params` are used as key. See [Query Keys](https://tanstack.com/query/latest/docs/framework/react/guides/query-keys) for more information.
 - `infiniteQueryOptions`
+  - `pageParamName` The query param name used for pagination, `"cursor"` by default.
   - The original `useInfiniteQuery` options.
   - [See more information](https://tanstack.com/query/latest/docs/framework/react/reference/useInfiniteQuery)
 - `queryClient`

packages/openapi-react-query/src/index.ts

@@ -110,7 +110,7 @@ export type UseInfiniteQueryMethod<Paths extends Record<string, Record<HttpMetho
     UseInfiniteQueryOptions<
       Response["data"],
       Response["error"],
-      InfiniteData<Response["data"]>,
+      InferSelectReturnType<InfiniteData<Response["data"]>, Options["select"]>,
       Response["data"],
       QueryKey<Paths, Method, Path>,
       unknown
@@ -125,7 +125,10 @@ export type UseInfiniteQueryMethod<Paths extends Record<string, Record<HttpMetho
   init: InitWithUnknowns<Init>,
   options: Options,
   queryClient?: QueryClient,
-) => UseInfiniteQueryResult<InfiniteData<Response["data"]>, Response["error"]>;
+) => UseInfiniteQueryResult<
+  InferSelectReturnType<InfiniteData<Response["data"]>, Options["select"]>,
+  Response["error"]
+>;
 
 export type UseSuspenseQueryMethod<Paths extends Record<string, Record<HttpMethod, {}>>, Media extends MediaType> = <
   Method extends HttpMethod,

packages/openapi-react-query/test/index.test.tsx

@@ -1087,5 +1087,69 @@ describe("client", () => {
       const allItems = result.current.data?.pages.flatMap((page) => page.items);
       expect(allItems).toEqual([1, 2, 3, 4, 5, 6]);
     });
+    it("should use return type from select option", async () => {
+      const fetchClient = createFetchClient<paths>({ baseUrl });
+      const client = createClient(fetchClient);
+
+      // First page request handler
+      const firstRequestHandler = useMockRequestHandler({
+        baseUrl,
+        method: "get",
+        path: "/paginated-data",
+        status: 200,
+        body: { items: [1, 2, 3], nextPage: 1 },
+      });
+
+      const { result, rerender } = renderHook(
+        () =>
+          client.useInfiniteQuery(
+            "get",
+            "/paginated-data",
+            {
+              params: {
+                query: {
+                  limit: 3,
+                },
+              },
+            },
+            {
+              getNextPageParam: (lastPage) => lastPage.nextPage,
+              initialPageParam: 0,
+              select: (data) => data.pages.flatMap((page) => page.items).filter((item) => item !== undefined),
+            },
+          ),
+        { wrapper },
+      );
+
+      // Wait for initial query to complete
+      await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+      expectTypeOf(result.current.data).toEqualTypeOf<number[] | undefined>();
+      expect(result.current.data).toEqual([1, 2, 3]);
+
+      // Set up mock for second page before triggering next page fetch
+      const secondRequestHandler = useMockRequestHandler({
+        baseUrl,
+        method: "get",
+        path: "/paginated-data",
+        status: 200,
+        body: { items: [4, 5, 6], nextPage: 2 },
+      });
+
+      // Fetch next page
+      await act(async () => {
+        await result.current.fetchNextPage();
+        // Force a rerender to ensure state is updated
+        rerender();
+      });
+
+      // Wait for second page to be fetched and verify loading states
+      await waitFor(() => {
+        expect(result.current.isFetching).toBe(false);
+        expect(result.current.hasNextPage).toBe(true);
+      });
+
+      expect(result.current.data).toEqual([1, 2, 3, 4, 5, 6]);
+    });
   });
 });