@react-aria/utils/src/domHelpers.ts

Spectrum UI components in React

export const getOwnerDocument = (el: Element | null | undefined): Document => {
  return el?.ownerDocument ?? document;
};

export const getOwnerWindow = (
  el: (Window & typeof global) | Element | null | undefined
): Window & typeof global => {
  if (el && 'window' in el && el.window === el) {
    return el;
  }

  const doc = getOwnerDocument(el as Element | null | undefined);
  return doc.defaultView || window;
};