v3.11.5 breaks typed routes on the client

[MonsterDeveloper]

What version of Hono are you using?

v3.11.9

What runtime/platform is your app running on?

Bun

What steps can reproduce the bug?

Link to TS Playground

What is the expected behavior?

Client should correctly transform the type of objects.

What do you see instead?

No response

Additional information

After an update to v3.11.9, the types for Hono client's responses in my app are now broken. The bug was introduced in v3.11.5 in PR #1806

Although transforming types to JSON works fine with simple objects, once you start using nested objects and interfaces, it falls apart.

The Jsonify utility from type-fest works fine, however. In the end of the playground I showed the correct types using this utility.

I believe the fix should be easy to implement (i.e. just use the code from type-fest).

[yusukebe]

Hi @MonsterDeveloper

Thanks for raising the issue. To think about this more deeply, can you show me the minimal code to reproduce your problem?

[yusukebe]

Related to https://github.com/orgs/honojs/discussions/1824

[MonsterDeveloper]

@yusukebe here's a link to a playground with a simple Hono app.

Please note how someMeta got turned into string for some reason, although the SampleInterface surely is losslessly jsonifiable.

[MonsterDeveloper]

It seems to me this is the issue with interfaces only. Plain types are transformed correctly.

I think this remark from type-fest's Jsonify is related to this behavior.

I'm not sure whether it is possible at all to make json transforms work with interfaces.

[yusukebe]

@MonsterDeveloper

How about using the JSONParsed as below?

export type JSONParsed<T> = T extends { toJSON(): infer J }
  ? (() => J) extends () => JSONObject
    ? J
    : JSONParsed<J>
  : T extends JSONPrimitive
  ? T
  : T extends Array<infer U>
  ? Array<JSONParsed<U>>
  : T extends object
  ? { [K in keyof T]: JSONParsed<T[K]> }
  : never

[MonsterDeveloper]

Seems to be working just fine. Thanks!