Using type-fest

export type PartialDeep<T, Opts extends PartialDeepOptions = {}> =
  T extends BuiltIns
  ? T
  : T extends Map<infer KeyType, infer ValueType>
    ? PartialMapDeep<KeyType, ValueType, Opts>
    : T extends Set<infer ItemType>
      ? PartialSetDeep<ItemType, Opts>
      : T extends ReadonlyMap<infer KeyType, infer ValueType>
        ? PartialReadonlyMapDeep<KeyType, ValueType, Opts>
        : T extends ReadonlySet<infer ItemType>
          ? PartialReadonlySetDeep<ItemType, Opts>
          : T extends ((...arguments: any[]) => unknown)
            ? T | undefined
            : T extends object
              ? T extends ReadonlyArray<infer ItemType>
                ? Opts['recurseIntoArrays'] extends true
                  ? ItemType[] extends T
                    ? readonly ItemType[] extends T
                      ? ReadonlyArray<PartialDeep<ItemType | undefined, Opts>>
                      : Array<PartialDeep<ItemType | undefined, Opts>>
                    : PartialObjectDeep<T, Opts>
                  : T
                : PartialObjectDeep<T, Opts>
              : unknown;

/**
Same as `PartialDeep`, but accepts only `Map`s and as inputs.
Internal helper for `PartialDeep`.
*/
type PartialMapDeep<KeyType, ValueType, Options extends PartialDeepOptions> =
  {} & Map<PartialDeep<KeyType, Options>, PartialDeep<ValueType, Options>>;

/**
Same as `PartialDeep`, but accepts only `Set`s as inputs.
Internal helper for `PartialDeep`.
*/
type PartialSetDeep<T, Options extends PartialDeepOptions> =
  {} & Set<PartialDeep<T, Options>>;

/**
Same as `PartialDeep`, but accepts only `ReadonlyMap`s as inputs.
Internal helper for `PartialDeep`.
*/
type PartialReadonlyMapDeep<
  KeyType, ValueType,
  Options extends PartialDeepOptions
> = {} & ReadonlyMap<
    PartialDeep<KeyType, Options>,
    PartialDeep<ValueType, Options>
  >;

/**
Same as `PartialDeep`, but accepts only `ReadonlySet`s as inputs.
Internal helper for `PartialDeep`.
*/
type PartialReadonlySetDeep<T, Options extends PartialDeepOptions> =
  {} & ReadonlySet<PartialDeep<T, Options>>;

/**
Same as `PartialDeep`, but accepts only `object`s as inputs.
Internal helper for `PartialDeep`.
*/
type PartialObjectDeep<
  ObjectType extends object,
  Options extends PartialDeepOptions
> = {
  [KeyType in keyof ObjectType]?: PartialDeep<ObjectType[KeyType], Options>
};