openapi-react-query throws with null values

[HugeLetters]

Description

openapi-react-query crashes if endpoint returns null.

Reproduction

any endpoint which returns null with useQuery exposed by this library

Expected result

null is both valid json and react-query allows to return it from queryFn

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

Line 144 in 781cf92

if (error || !data) {

This line causes the issue - !data should be replaced with data!==undefined

Checklist

• I’m willing to open a PR (see CONTRIBUTING.md)

[kerwanp]

Hi, happy to accept a PR to fix this issue!

[BenJeau]

Affected by the same issue whenever a useMutation data response is just an empty string

[agrahamg]

This is also happening for me in mutations for endpoints returning a 204

  /example:
    post:
      parameters: []
      responses:
        '204':
          description: 'No content'

The fetchClient returns undefined which errors in the mutation.

[martmalo]

Also encountered this issue on http status 204. React query mutation throws undefined error.

[HugeLetters]

@martmalo what is the mutation supposed to return? Is it like a null or an empty string?

Since I'm working on the PR I would like to know if I need to handle some extra case - right now the fix is that we allow to return anything from mutation except undefined. undefined is allowed in mutations by react-query but it's not valid JSON so it's not like you can get it as a response.

You can check what it's supposed to return in devtools in the network tab by checking the associated request

[martmalo]

@martmalo what is the mutation supposed to return? Is it like a null or an empty string?

Since I'm working on the PR I would like to know if I need to handle some extra case - right now the fix is that we allow to return anything from mutation except undefined. undefined is allowed in mutations by react-query but it's not valid JSON so it's not like you can get it as a response.

You can check what it's supposed to return in devtools in the network tab by checking the associated request

I think you already handled my case because 204 by default is no content response and the response body is undefined.

[gt-vs-3141]

@HugeLetters, should we be able to retrieve undefined responses from a mutation? When the API responds with 204, the body is undefined, so currently, the mutation doesn't support successful responses without a body definition.

Throwing for undefined data is a mistake since you mentioned that react-query supports it. Types might need to be changed to support it correctly, but a type error is preferable to a runtime error.

React Query doesn't care about status codes, but open API-react-query might consider it for such cases. Do you think it makes sense?