Make Simplify works for deep nesting

[linbudu599]

This PR makes Simplify type works for computed types with deep nesting.

Example:

type Foo = {
  foo: string;
  bar: number;
  baz: boolean;
}

type Result = {
  [K in keyof Foo]: Pick<Foo, K>
}

// {
//     foo: Pick<Foo, "foo">;
//     bar: Pick<Foo, "bar">;
//     baz: Pick<Foo, "baz">;
// }
type SimplifiedResult = Simplify<Result>;

With deep version:

type DeepSimplify<T> = { [KeyType in keyof T]: T[KeyType] extends object ? DeepSimplify<T[KeyType]> : T[KeyType] } & {};

type Result = {
  [K in keyof Foo]: Pick<Foo, K>
}

// {
//     foo: {
//         foo: string;
//     };
//     bar: {
//         bar: number;
//     };
//     baz: {
//         baz: boolean;
//     };
// }
type DeepSimplifiedResult = DeepSimplify<Result>;

[linbudu599]

Seems like this change breaks the other type behaviour in test cases, like PartialOnUndefinedDeep, maybe we should bring a new type called SimplifyDeep ? @sindresorhus

[Emiyaaaaa]

Seems like this change breaks the other type behaviour in test cases, like PartialOnUndefinedDeep, maybe we should bring a new type called SimplifyDeep ? @sindresorhus

SimplifyDeep is existing but it's in type-fest/source/merge-deep, make it to be a stable type will be better

[sindresorhus]

Yes. It should be a separate type. That internal type should be properly exposed.

[sindresorhus]

Bump :)