Check if element is in viewport

elementInViewport.js

/**
 * Check if element is in viewport
 * @param  {Node} el
 * @return {Object}
 */
export function elementInViewport(el) {
  let top = el.offsetTop;
  let left = el.offsetLeft;
  let width = el.offsetWidth;
  let height = el.offsetHeight;

  while(el.offsetParent) {
    el = el.offsetParent;
    top += el.offsetTop;
    left += el.offsetLeft;
  }

  return (
    top < (window.pageYOffset + window.innerHeight) &&
    left < (window.pageXOffset + window.innerWidth) &&
    (top + height) > window.pageYOffset &&
    (left + width) > window.pageXOffset
  );
}