/**
 * Returns the activeElement, even when they are inside a shadowRoot.
 * (If an element in a shadowRoot is focused, document.activeElement
 * returns the shadowRoot host.
 *
 * @returns {Element}
 */
export function getDeepActiveElement() {
  let host = document.activeElement || document.body;
  while (host && host.shadowRoot && host.shadowRoot.activeElement) {
    host = host.shadowRoot.activeElement;
  }
  return host;
}