TypeScript integration: how to use ArraySchema properly?

[rockychordtea]

I didn't find any documentation on ArraySchema usage.
Specifically, it's not clear what its type parameters mean.

declare class ArraySchema<TIn extends any[] | null | undefined, TContext, TDefault = undefined, TFlags extends Flags = ''> ...

With just a single array-type parameter it doesn't work for obvious reason: the second parameter is required:

const foo: yup.ArraySchema<number[]> = yup.array().of(yup.number().defined()).defined()

triggering an error:

Generic type 'ArraySchema<TIn, TContext, TDefault, TFlags>' requires between 2 and 4 type arguments.

However, passing any as the second parameter doesn't make it work either:

const foo: yup.ArraySchema<number[], any> = yup.array().of(yup.number().defined()).defined()

and fails with this error:

Type 'ArraySchema<number[], AnyObject, "", "">' is not assignable to type 'ArraySchema<number[], any, undefined, "">'.
  Type '""' is not assignable to type 'undefined'.

Guessing further, after sett the third parameter to any removes error messages:

const foo: yup.ArraySchema<number[], any, any> = yup.array().of(yup.number().defined()).defined()

I wonder, what is the correct way to use this and what is the meaning of the parameters?

Version: 1.0.0-beta.8

[jquense]

The last attempt with any works fine, ArraySchema<number[], any, undefined, ""> is probably the most correct. I need to update the generic defaults here tho so that you don't need to provide them like ObjectSchema

[karlhorky]

In case you cannot use any in your codebase, unknown seems to also work:

const fileSchema: ArraySchema<File[], unknown, ''> =
  array()
    .of(
      object({
        ...
      }).required()
    ).required()