function getScrollParent(element) {
    // Return body, `getScroll` will take care to get the correct `scrollTop` from it
    if (!element) {
      return document.body;
    }

    switch (element.nodeName) {
      case 'HTML':
      case 'BODY':
        return element.ownerDocument.body;
      case '#document':
        return element.body;
    }

    // Firefox want us to check `-x` and `-y` variations as well

    var _getStyleComputedProp = getStyleComputedProperty(element),
        overflow = _getStyleComputedProp.overflow,
        overflowX = _getStyleComputedProp.overflowX,
        overflowY = _getStyleComputedProp.overflowY;

    if (/(auto|scroll|overlay)/.test(overflow + overflowY + overflowX)) {
      return element;
    }

    return getScrollParent(getParentNode(element));
  }
Returns the scrolling parent of the given element
@method
@memberof Popper.Utils
@argument {Element} element
@returns {Element} scroll parent