GenType does not handle JSON types in Core properly

[jmagaram]

Sample project:

https://github.com/jmagaram/functors

Look at file Simple.res with the code:

@genType
let hello = JSON.Encode.string("hello")

The TypeScript is...

import * as SimpleJS from './Simple.res.mjs';
import type {t as Core__JSON_t} from '@rescript/core/src/Core__JSON.gen';
export const hello: Core__JSON_t = SimpleJS.hello as any;

And the error on the second line is...

Cannot find module '@rescript/core/src/Core__JSON.gen' or its corresponding type declarations.

[jmagaram]

Might be related to #6563

[tsnobip]

unfortunately, given typescript does not plan to have a JSON type, we'll have to advise users to create a shim for the JSON type for now.

[cristianoc]

What type should be exported ideally, given that TS does not have a builtin?
Or should it just be any or something like that?

[zth]

unknown is probably the best candidate if we can't find anything that's better. It's slightly better than any, and I also believe it's what JSON.parse returns.

[tsnobip]

What type should be exported ideally, given that TS does not have a builtin? Or should it just be any or something like that?

I guess ideally it would use something like that:

type Json =
  | string
  | number
  | boolean
  | null
  | Json[]
  | { [key: string]: Json };

but you can't define this inline given it's a recursive type.