fix(types): rm ExcludeEmptyObject to fix massively increased type instantiations

[m-shaka]

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

It's super weird, but if ExcludeEmptyObject is outside of hono-base.ts, "Type instantiation is excessively deep and possibly infinite." error occurs.
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#3443 (comment)

I don't know the cause at all, it may be a kind of cache issue, though

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All modified and coverable lines are covered by tests ✅

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@@           Coverage Diff            @@
##             main    #3507    +/-   ##
========================================
  Coverage   95.58%   95.58%            
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  Files         155      155            
  Lines        9357     9357            
  Branches     2873     2761   -112     
========================================
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  Misses        413      413            

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[m-shaka]

Weird again.

The reason why I added ExcludeEmptyObject is that schema type with empty object type broke RPC type.
For example, T in code below is never without ExcludeEmptyObject.

const app = new Hono().route('/', new Hono().get('/foo', c => c.json({ ok: true })))
type T = Client<typeof app>

But, replacing Hono with HonoBase in Client fixed the problem

[m-shaka]

🤔

const app = new Hono()
  .route('/', new Hono().get('/foo', c => c.json({ ok: true })))
type Extract1<T> = T extends Hono<any, infer S, any> ? S : never
type Extract2<T> = T extends HonoBase<any, infer S, any> ? S : never
type R1 = Extract1<typeof app> // {}
type R2 = Simplify<Extract2<typeof app>> // {} | { '/foo': ... }

typeof app is HonoBase, but I don't suppose it explains this behaviour

[yusukebe]

@m-shaka

Is that behavior related to the following weird stuff?:

[m-shaka]

I think that's a matter of display.
The return type of route is HonoBase and it's correct, but in src/hono-base.ts its name is Hono. If you rename class Hono with HonoBase in src/hono-base.ts, you see always HonoBase in the widget.

[yusukebe]

@m-shaka

Ah, understand. Thanks!

[yusukebe]

Hi @m-shaka

I can reproduce it. Indeed, it's weird.

It's super weird, but if ExcludeEmptyObject is outside of hono-base.ts, "Type instantiation is excessively deep and possibly infinite." error occurs.

How about putting ExcludeEmptyObject in hono-base.ts instead of utils/types.ts (it was my suggestion to move it to utils/types.ts!)?

[m-shaka]

We don't need ExcludeEmptyObject anymore thanks to https://github.com/honojs/hono/pull/3507/files#diff-786ee0c27ee2360ff838e12e8de257697060cc7bddcb8cb461c8ba1faa664aceR163 and also it will reduce the number of type instantiations more.

[yusukebe]

LGTM!

[yusukebe]

@m-shaka

Okay! Let's go with it. Thank you.