factory.createMiddleware() breaks the client's typing.

[satoshun00]

What version of Hono are you using?

4.6.17

What runtime/platform is your app running on? (with version if possible)

Node

What steps can reproduce the bug?

When using middleware created with factory.createMiddleware() in .use, the client's type inference stops working.

Previously, an issue was reported regarding createMiddleware() at #3122, which seems to have been fixed. However, it appears a similar issue is occurring with factory.createMiddleware().

Below is a code example for reproduction:
TypeScript playground

import { Hono, type Env } from 'hono';
import { hc } from 'hono/client';
import { createFactory, createMiddleware } from 'hono/factory';

const factory = createFactory<Env>();

const middleware = factory.createMiddleware(async (_, next) => {
  console.log('Middleware');
  await next();
});

// There will be no type errors when creating middleware with createMiddleware()
// const middleware = createMiddleware(async (_, next) => {
//   console.log('Middleware');
//   await next();
// });

const app = new Hono()
  .use('*', middleware)
  .get('/users', (c) => c.text('GET /users'));

const client = hc<typeof app>('');
console.log(client.users.$get()); // This should typecheck

What is the expected behavior?

No response

What do you see instead?

No response

Additional information

No response

[yusukebe]

Hi @satoshun00 Thanks! This is a bug. I'll fix it.

[yusukebe]

@satoshun00

This may be fixed in the new version v4.6.18. Can you try it?

[satoshun00]

@yusukebe
Thank you for the quick response!
I have confirmed that the fix works in my project as well.