Get Scrollable Parent

getScrollableParent.js

function getScrollParent(node) {
  const isElement = node instanceof HTMLElement;
  const overflowY = isElement && window.getComputedStyle(node).overflowY;
  const isScrollable = overflowY !== 'visible' && overflowY !== 'hidden';

  if (!node) {
    return null;
  } else if (isScrollable && node.scrollHeight >= node.clientHeight) {
    return node;
  }

  return getScrollParent(node.parentNode) || document.body;
}

export default getScrollParent;

Hi everyone, a version supporting shadow dom

https://gist.github.com/oscarmarina/3a546cff4d106a49a5be417e238d9558