function getFocusables (element, keyboardOnly = false) {
  let focusableEls = Array.from(element.querySelectorAll(focusableElSelector))

  // filter out elements with display: none
  focusableEls = focusableEls.filter(
    focusableEl => window.getComputedStyle(focusableEl).display !== 'none'
  )

  if (keyboardOnly === true) {
    focusableEls = focusableEls.filter(
      focusableEl => focusableEl.getAttribute('tabindex') !== '-1'
    )
  }
  return focusableEls
}
Get a NodeList of all focusable DOM nodes within an element
@param {HTMLElement} element HTML element to get focusable list of DOM nodes from.
@param {Boolean} keyboardOnly Should get only keyboard accessible nodes?
@returns {NodeList} List of all focusable DOM nodes