SolidJS createSingle TypeScript V2

/*
 * createSingle is a "sugar" wrapper around the SolidJS function createSignal:
 * const single = createSingle(value, options?);
 * single (and single.s!) return the original setter, augmented with .g, .s, .r, and .w.
 * single.g (and single.g.g!) return the original getter, augmented with .g and .r, for
 * passing read-only access to other places ("segmentation of access").
 * single.r, single.g.r, and single.g() return the read-only value by calling the getter.
 * single.w = value, single(value), and single.s(value) change the value by calling the setter.
 * single.w also works for read-modify-write (++, --, and op=) but you should use .r otherwise.
 * Notes: single is the *setter*, so single() is not a valid call signature.
 */
import { createSignal, Accessor, Setter } from "solid-js";
export type SignalOptions<T> = { equals?: false | ((prev: T, next: T) => boolean) };

type ReaderPrototype<T> = {
  (): T;
  get g (): SingleReader<T>;
  get r (): T;
};
export type SingleReader<T> = Accessor<T> & ReaderPrototype<T>;
type AccessorPrototype<T> = {
  (newv: T): T;
  get g (): SingleReader<T>;
  get r (): T;
  get s (): SingleAccessor<T>;
  get w (): T;
  set w (newv: T);
};
export type SingleAccessor<T> = Setter<T> & AccessorPrototype<T>;
export type CreateSingle<T> = {
  (iv: T, options?: SignalOptions<T>): SingleAccessor<T>;
  accessorPrototype: AccessorPrototype<T>;
  readerPrototype: ReaderPrototype<T>;
};

export default function createSingle<T> (iv: T, options?: SignalOptions<T>): SingleAccessor<T> {
  const cs = createSingle as CreateSingle<T>;

  if (!cs.readerPrototype) cs.readerPrototype = Object.setPrototypeOf({
    get g () { return this; },
    get r () { return this(); }
  }, Function.prototype) as ReaderPrototype<T>;

  if (!cs.accessorPrototype) cs.accessorPrototype = Object.setPrototypeOf({
    get r () { return this.g(); },
    get w () { return this.g(); },
    set w (newv: T) { this(newv); }
  }, Function.prototype) as AccessorPrototype<T>;

  const [getter, setter] = createSignal(iv, options);
  // eslint-disable-next-line
  if (!('r' in getter)) Object.setPrototypeOf(getter, cs.readerPrototype);
  if (!('w' in setter)) Object.setPrototypeOf(setter, cs.accessorPrototype);
  if (!('g' in setter)) Object.defineProperty(setter, 'g', { value: getter, writable: false });
  return setter as SingleAccessor<T>;
}