React-query can't handle return data that's undefined (From 204 response returned by openapi-fetch)

[wheelebin]

openapi-react-query version

0.2.5

Description

Summary

I've set up a "standard" implementation of openapi-fetch with openapi-react-query. I have an endpoint that returns a 204 response with no data in the body, and this causes react-query to throw an error due to the data returned from openapi-fetch being undefined.

Caution

Query data cannot be undefined. Please make sure to return a value other than undefined from your query function. Affected query key: ["get","/some-endpoint-with-empty-response",{"params":{"query":{"key":"test-widget"}}}]

Workaround

I'm able to work around this by reconfiguring our endpoint to return status 200 instead of 204 and then setting the openapi-fetch parseAs to "stream" via the openapi-react-query options.

This seems to work since the 204 early return conditional that returns undefined gets skipped, and the parseAs: stream skips any data parsing while handling the "200" response.

const testQuery = $api.useQuery("get", "/some-endpoint-with-empty-response", {
    params: { query: { key: "test-widget" } },
    parseAs: "stream"
  });

However, I'm not a fan of this workaround and would like to know if openapi-fetch & openapi-react-query could handle these 204 responses more elegantly.

Research

I found a discussion on GitHub about this issue and also located the commit that changed the return data from an empty object to undefined.

• Discussion: Why is data an empty object for a 204 response? #1868
• Commit: 267977e

The empty data object would most likely fix my problem. However, since the above commit replaced the empty data object with undefined, I'm curious to know:

• Is this behavior intended to work with openapi-react-query/react-query?
• Are there any configurations I might have missed that would prevent undefined values from being returned to react-query?

I was looking around in the source code to see if I could "hook" into the query function before it returns anything (similar to how the onResponse middleware works), but I could not find anything that would support this behavior.

Thanks in advance! :)

Reproduction

• Setup openapi-fetch, openapi-react-query as the docs state.
• Setup an API endpoint that returns 204 status code.
• Call the API endpoint with openapi-react-query
• This should cause react-query to throw an error due to the return data being undefined once the request has finished.

Expected result

When dealing with a 204 status code, openapi-fetch should return data that is supported by react-query (such as an empty object or null?)

Extra

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

[wheelebin]

I've created a PR (#2235) that would solve this issue for the react-query users without affecting the openapi-fetch package.

It's a small change that only modifies the queryFn in the openapi-react-query package.

Could be a possible solution?