index.ts

import { AnyArray } from "../any-array";
import { Builtin } from "../built-in";
import { IsTuple } from "../is-tuple";
import { IsUnknown } from "../is-unknown";

export type DeepReadonly<Type> = Type extends Exclude<Builtin, Error>
  ? Type
  : Type extends Map<infer Keys, infer Values>
  ? ReadonlyMap<DeepReadonly<Keys>, DeepReadonly<Values>>
  : Type extends ReadonlyMap<infer Keys, infer Values>
  ? ReadonlyMap<DeepReadonly<Keys>, DeepReadonly<Values>>
  : Type extends WeakMap<infer Keys, infer Values>
  ? WeakMap<DeepReadonly<Keys>, DeepReadonly<Values>>
  : Type extends Set<infer Values>
  ? ReadonlySet<DeepReadonly<Values>>
  : Type extends ReadonlySet<infer Values>
  ? ReadonlySet<DeepReadonly<Values>>
  : Type extends WeakSet<infer Values>
  ? WeakSet<DeepReadonly<Values>>
  : Type extends Promise<infer Value>
  ? Promise<DeepReadonly<Value>>
  : Type extends AnyArray<infer Values>
  ? Type extends IsTuple<Type>
    ? { readonly [Key in keyof Type]: DeepReadonly<Type[Key]> }
    : ReadonlyArray<DeepReadonly<Values>>
  : Type extends {}
  ? { readonly [Key in keyof Type]: DeepReadonly<Type[Key]> }
  : IsUnknown<Type> extends true
  ? unknown
  : Readonly<Type>;