naive-ui/es/affix/src/utils.mjs

A Vue 3 Component Library. Fairly Complete, Theme Customizable, Uses TypeScript, Fast

export function getScrollTop(target) {
  return target instanceof HTMLElement ? target.scrollTop : window.scrollY;
}
export function getRect(target) {
  return target instanceof HTMLElement ? target.getBoundingClientRect() : {
    top: 0,
    bottom: window.innerHeight
  };
}