block10.ts

const getScrollPercentage = (startMarker: HTMLElement, endMarker: HTMLElement): number => {
  const offsetFromTop = getPosRelativeToBody(startMarker)
  const total = getPosRelativeToBody(endMarker) - offsetFromTop - window.innerHeight
  const progress = (((window.scrollY - offsetFromTop) / total) * 100)
  return progress
}

const getPosRelativeToBody = (el: HTMLElement): number => {
  return Math.abs(
    document.documentElement.getBoundingClientRect().top - el.getBoundingClientRect().top,
  );
}

export {
  getScrollPercentage
}