useWindowSize.js

function useWindowSize() {
  const width = useSyncExternalStore(
    subscribe,
    () => window.innerWidth,
    () => 0,
  );

  const height = useSyncExternalStore(
    subscribe,
    () => window.innerHeight,
    () => 0,
  );

  return {
    width,
    height,
  };
}

function subscribe(listener) {
  window.addEventListener("resize", listener);

  return () => {
    window.removeEventListener("resize", listener);
  };
}