/**
 * Gets the scroll value of the given element in the given side (top and left)
 * @method
 * @memberof Popper.Utils
 * @argument {Element} element
 * @argument {String} side `top` or `left`
 * @returns {number} amount of scrolled pixels
 */
export default function getScroll(element, side = 'top') {
  const upperSide = side === 'top' ? 'scrollTop' : 'scrollLeft';
  const nodeName = element.nodeName;

  if (nodeName === 'BODY' || nodeName === 'HTML') {
    const html = element.ownerDocument.documentElement;
    const scrollingElement = element.ownerDocument.scrollingElement || html;
    return scrollingElement[upperSide];
  }

  return element[upperSide];
}