transformResponse in enhanceEndpoints returning Promise type when trying to transform the type of the response

[cini9]

Following the update to V1.9.4, with the ability to override TS type of the original data in transformResponse of enhanceEndpoints, the response type I am receiving in my components are being additionally transformed to add a Promise<> type of my desired response type.

I am using codegen to generate types from my backend, but need to transform that response to extract lower-level data from the raw graphql query response.

type TransformedGetUser = GetUserQuery['getUser']
type TransformedGetUsers = GetUsersQuery['getUsers']

type Definitions = DefinitionsFromApi<typeof generatedUserApi>
type TagTypes = TagTypesFromApi<typeof generatedUserApi>

type UpdatedDefinitions = Omit<Definitions, 'getUsers' | 'getUser'> & {
  getUsers: OverrideResultType<Definitions['getUsers'], TransformedGetUsers>
  getUser: OverrideResultType<Definitions['getUser'], TransformedGetUser>
}

const userApi = generatedUserApi.enhanceEndpoints<TagTypes, UpdatedDefinitions>(
  {
    endpoints: {
      getUsers: {
        providesTags: ['User'],
        transformResponse: (response: GetUsersQuery): TransformedGetUsers =>
          response.getUsers,
      },
      getUser: {
        providesTags: ['User'],
        transformResponse: (response: GetUserQuery): TransformedGetUser =>
          response.getUser,
      },
    },
  }
)

This gives me the typing in the components in the screen shot below, with my correct type (id: string, firstName: string, etc) followed by the Promise<...> type.

When I try to use the data returned from these queries, I'm getting a 'property id does not exist on type Promise< .... >'

Is there any way to tell RTK to not add the Promise type when we are overriding the response type in transformResponse ?

Thanks in advance for your help !

[qtn-g]

@dmitrigrabov did you find any solution ?

Is there a way that I can help ?

[Mozzarella123]

The main problem is that transformResponse can return Promise in types. And when we use query data it becomes MaybePromise

redux-toolkit/packages/toolkit/src/query/endpointDefinitions.ts

Line 79 in f31ff77

): ResultType | Promise<ResultType>

@cini9

[cini9]

@Mozzarella123 Thanks for the update ! Is this the correct behaviour ? If so, how can I override this to obtain only the ResultType in my components ?

[EskiMojo14]

Hi there, thanks for the report! Apologies for the slow response.

The issue appears to be that the utility type used to extract the result from the provided type didn't account for Promises, as the actual execution unwraps that promise.

I've opened #3500 that should fix this - if someone could try the build that's created from that PR, that'd be greatly appreciated.

In terms of overriding result types, we're investigating (over at #3485) the possibility of replacing enhanceEndpoints entirely, with two functions - addTagTypes and enhanceEndpoint. This would greatly simplify typings and thus use cases such as replacing return types.

const enhanced = api
  .addTagTypes('tag1', 'tag2')
  .enhanceEndpoint('query1', { providesTags: ['tag1'] })
  .enhanceEndpoint('mutation2', (definition) => {
    definition.invalidatesTags = ['tag2'];
  })

This is of course a big breaking change, so it would be part of RTK 2.0, clearly communicated, and a codemod would most likely be provided to ease the transition.

[qtn-g]

Hey, thanks for the update

I've tried on my side and it sounds good !

[cini9]

Hey @EskiMojo14 thanks for the fix ! I've checked it out and it seems to fix the Promise issue on my side as well !

[EskiMojo14]

great 😄

both of the other co-maintainers are at conferences this week so I'm unsure when we can get the fix reviewed, merged and published - will try to get it prioritised when possible 🙂

[qtn-g]

Hey @EskiMojo14,

Do you have any idea when it can be checked and released ?

[EskiMojo14]

it's been merged into master, but i'm not sure when the next release will be

[annaet]

@EskiMojo14 Any chance of getting a new release out including this fix? It would be really useful for my team 😄

[markerikson]

I'll look at trying to get out another release sometime today.