Array-type query params are always exploded

[codeth]

Apologies if I'm missing something obvious, but I'm seeing something unexpected with our generated fetch client.

Our backend API does not support exploded array query params (the Swagger specs specify explode: false) but it looks like the HTTP client does nothing to support the unexploded style, it just maps the values and joins them https://github.com/acacode/swagger-typescript-api/blob/main/templates/base/http-clients/fetch-http-client.ejs#L85

I didn't find an obvious config option that would change this behaviour, other than overriding the template or class method, which I was hoping to avoid.

There was an old issue where someone was having the opposite problem, and it looks like the fix applied there actually abandoned any OOTB support the unexploded style #222

Perhaps this is by design - I'm happy work around it for our project, but since I couldn't find any concrete docs/answers I think it's worth asking, and maybe should be called out that param schemas using explode have no support/effect on the generated client.

Example:

paths:
  /some/api/path:
    get:
      parameters:
        - name: test
          in: query
          style: form
          explode: false
          schema:
            type: array
            items:
              type: string
              enum:
                - hello
                - world
                - yay

Expected request URL:

GET /some/api/path?test=hello,yay

Actual request URL:

GET /some/api/path?test=hello&test=yay

[smorimoto]

Found 2 possible duplicate issues:

1. Array query param values are serialized with the (non-default) comma separated style #222
2. Strange behavior with query params since version 9 #260

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate. It was marked as a duplicate over 3 days ago with no further activity. If you believe this was closed in error, please comment and we'll re-evaluate.

[codeth]

@smorimoto The referenced issues are related, but both are 5 years old and neither actually address mine.

I've found no documentation or record to suggest that only one param style is supported. If the intention is to do nothing with explode, it should be documented as such.

#222 I had already referenced as the root cause of what I'm reporting as an issue.

#260 was closed without a clear resolution.

[morgan-coded]

Checking whether a Fetch-only first pass for #1541 fits the direction here. I'd carry the existing style and explode metadata into generated query handling and support OpenAPI 3 query arrays with style: form and explicit explode: false, while omitted/default and explode: true keep the current repeated-key behavior. The focused tests would cover generated output and captured request URLs for all three explode states, including comma and space values. Axios, Ky, objects, other styles or locations, and allowReserved would stay out of this pass. Would you be open to that boundary?

[morgan-coded]

Re-ran the Fetch case against released swagger-typescript-api 13.12.6. A query array declared as style: form, explode: false still generates /a?tags=x&tags=y&tags=z; OAS 3.0.3 expects /a?tags=x,y,z. Explicit explode: true and a spec-silent array both keep the repeated-key URL, and the generated clients for all three cases are byte-identical.

My offer stays Fetch-only: only spec-explicit style/explode would change output, while spec-silent behavior stays byte-identical. Would you prefer that boundary, or should I drop this?

[codeth]

For our use case that would be great. I just worked around it with a class override in the end. It's just an honesty gap - The implementation ignores it, and the documentation doesn't mention it. Up to maintainer.