JsonifyObject

type JsonifyObject<BaseType, Marker extends string> = {
    [K in keyof BaseType as K extends symbol
        ? never
        : BaseType[K] extends (...args: unknown[]) => unknown
          ? never
          : K]:
        | JsonifyWithCirculars<
              Exclude<BaseType[K], undefined>,
              Marker
          >
        | Extract<BaseType[K], undefined>
        | Marker;
};

type JsonifyObject<BaseType, Marker extends string> = {
    [K in keyof BaseType as K extends symbol
        ? never
        : BaseType[K] extends (...args: unknown[]) => unknown
          ? never
          : K]:
        | JsonifyWithCirculars<
              Exclude<BaseType[K], undefined>,
              Marker
          >
        | Extract<BaseType[K], undefined>
        | Marker;
};