Merge pull request #3500 from reduxjs/transform-response-promise

Fix TransformedResponse type to unwrap promise

Author: EskiMojo14

packages/toolkit/src/query/endpointDefinitions.ts

@@ -17,6 +17,7 @@ import type {
   OmitFromUnion,
   CastAny,
   NonUndefined,
+  UnwrapPromise,
 } from './tsHelpers'
 import type { NEVER } from './fakeBaseQuery'
 import type { Api } from '@reduxjs/toolkit/query'
@@ -797,7 +798,9 @@ export type TransformedResponse<
 > = K extends keyof NewDefinitions
   ? NewDefinitions[K]['transformResponse'] extends undefined
     ? ResultType
-    : ReturnType<NonUndefined<NewDefinitions[K]['transformResponse']>>
+    : UnwrapPromise<
+        ReturnType<NonUndefined<NewDefinitions[K]['transformResponse']>>
+      >
   : ResultType
 
 export type OverrideResultType<Definition, NewResultType> =

packages/toolkit/src/query/tests/createApi.test.ts

@@ -581,16 +581,13 @@ describe('endpoint definition typings', () => {
         enhancedApi.endpoints.query1.initiate()
       )
       expect(queryResponse.data).toEqual({ value: 'transformed' })
-      expectType<Transformed | Promise<Transformed> | undefined>(
-        queryResponse.data
-      )
+      expectType<Transformed | undefined>(queryResponse.data)
 
       const mutationResponse = await storeRef.store.dispatch(
         enhancedApi.endpoints.mutation1.initiate()
       )
       expectType<
-        | { data: Transformed | Promise<Transformed> }
-        | { error: FetchBaseQueryError | SerializedError }
+        { data: Transformed } | { error: FetchBaseQueryError | SerializedError }
       >(mutationResponse)
       expect('data' in mutationResponse && mutationResponse.data).toEqual({
         value: 'transformed',