Improve middleware type definition

[yicrotkd]

Changes

This PR updates the Middleware type definition to ensure that either onRequest or onResponse must be provided, as reflected in the error:

"Middleware must be an object with one of onRequest() or onResponse()"

(see #1916)

The new type definition introduces a union that enforces this behavior, allowing the absence of both methods to be detected at compile time.

How to Review

Please review the changes to ensure that the new type definition accurately reflects the expected behavior. The key point is that a type error should occur only if neither onRequest nor onResponse is provided. Additionally, please check that existing middleware implementations are unaffected by this change.

Checklist

• Unit tests updated
• docs/ updated (if necessary)
• pnpm run update:examples run (only applicable for openapi-typescript)

Closes #1916

[changeset-bot]

🦋 Changeset detected

Latest commit: 5a0c65e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
openapi-fetch	Patch
openapi-react-query	Patch

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[drwpow]

Great fix, and great test! Happy to merge this, but first we need a patch changeset to release this (see comment for instructions)

[yicrotkd]

Thank you! I've added a patch changeset.

[drwpow]

Thank you!

[topaxi]

With this change, it is no longer possible to have classes implement the Middleware interface.

class MyMiddleware implements Middleware { ... }

Results in:

error TS2422: A class can only implement an object type or intersection of object types with statically known members.