get-scroll-width.ts

let scrollWidth: null | number = null;

export const getScrollWidth = (): number => {
  if (scrollWidth !== null) {
    return scrollWidth;
  }

  const el = document.createElement('div');
  el.style.position = 'fixed';
  el.style.zIndex = '-1';
  el.style.visibility = 'hidden';
  el.style.overflowY = 'scroll';
  el.style.width = '100%';
  el.style.height = '1px';
  document.body.appendChild(el);

  scrollWidth = el.offsetWidth - el.clientWidth;
  document.body.removeChild(el);

  return scrollWidth;
};