Extract unwrapped type from Any.Type

[expelledboy]

🍩 Feature Request

How do you get the underlying type T from Any.Type<T>?

import { Test, Any } from "ts-toolbelt";

const {checks, check} = Test

type RootType = number;
type Wrapped = Any.Type<RootType>;
type Unwrapped = Any.ExtractType<Wrapped>; // This is what I am looking for

checks([
    check<Unwrapped, RootType, Test.Pass>(),
])

Heres an example of where you would use it:

import { Any } from "ts-toolbelt";
import { Either } from "fp-ts/lib/Either";

// The library exports the following API to create terms given a object containing values
// It returns the module but with the wrapped opaque sub-types
export type Term<T extends Record<string, any>> = {
  [K in keyof T]: Any.Type<T[K], K>;
};

// This is really what I would like to work, or ask if there is an existing feature
// This looks like it should work.. and I have tried messing around with this for the last 2 hours
type ExtractType<T extends Any.Type<infer V>> = V;

// I wish to export an additional API parameterized with a type created using Term/1
export type Encode<T extends Record<string, any>> = {
  [K in keyof T]: (value: ExtractType<T[K]>) => Either<Error, T[K]>;
};

Here is how I desire to use the above generic types:

import { Term, Encode } from "./library.d"
import * as E from "fp-ts/lib/Either";

type MyTerm = Term<{
  Age: number;
}>

// I want to type the encode function from number -> Any.Type<Number>, ignoring the Maybe
const encodeAge: Encode<MyTerm>["Age"] = (age) => {
  if (age < 0) return E.left(new Error("Age out of bounds"));
  else return E.right(age as MyTerm["Age"]);
};

[expelledboy]

It seems that Any.Type needs to store the base type in an sub property, as per https://github.com/kourge/ts-brand

See https://github.com/kourge/ts-brand/blob/80e34f96c9bc6658b45f13bdbb02279a47cc062d/src/index.ts#L44

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.