fix(openapi-react-query): mutation results type

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

@@ -156,13 +156,16 @@ export type UseMutationMethod<Paths extends Record<string, Record<HttpMethod, {}
   Path extends PathsWithMethod<Paths, Method>,
   Init extends MaybeOptionalInit<Paths[Path], Method>,
   Response extends Required<FetchResponse<Paths[Path][Method], Init, Media>>, // note: Required is used to avoid repeating NonNullable in UseQuery types
-  Options extends Omit<UseMutationOptions<Response["data"], Response["error"], Init>, "mutationKey" | "mutationFn">,
+  TOnMutateResult = unknown,
 >(
   method: Method,
   url: Path,
-  options?: Options,
+  options?: Omit<
+    UseMutationOptions<Response["data"], Response["error"], Init, TOnMutateResult>,
+    "mutationKey" | "mutationFn"
+  >,
   queryClient?: QueryClient,
-) => UseMutationResult<Response["data"], Response["error"], Init>;
+) => UseMutationResult<Response["data"], Response["error"], Init, TOnMutateResult>;
 
 export interface OpenapiQueryClient<Paths extends {}, Media extends MediaType = MediaType> {
   queryOptions: QueryOptionsFunction<Paths, Media>;

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

@@ -792,6 +792,30 @@ describe("client", () => {
 
         await waitFor(() => rendered.findByText("data: Hello, status: success"));
       });
+
+      it("should type mutate results properly", async () => {
+        const fetchClient = createFetchClient<paths>({ baseUrl });
+        const client = createClient(fetchClient);
+
+        const onMutateReturnValue = { someArray: [1, 2, 3], someString: "abc" };
+        type expectedOnMutateResultType = typeof onMutateReturnValue | undefined;
+
+        const result = renderHook(
+          () =>
+            client.useMutation("put", "/comment", {
+              onMutate: () => onMutateReturnValue,
+              onError: (err, _, onMutateResult, context) => {
+                assertType<expectedOnMutateResultType>(onMutateResult);
+              },
+              onSettled: (_data, _error, _variables, onMutateResult, context) => {
+                assertType<expectedOnMutateResultType>(onMutateResult);
+              },
+            }),
+          { wrapper },
+        );
+
+        assertType<expectedOnMutateResultType>(result.result.current.context);
+      });
     });
 
     describe("mutateAsync", () => {