document.body : null;\n\n  // NOTE: 1 DOM access here\n  let offsetParent = element.offsetParent || null;\n  // Skip hidden elements which don't have an offsetParent\n  while (offsetParent === noOffsetParent && element.nextElementSibling) {\n    offsetParent = (element = element.nextElementSibling).offsetParent;\n  }\n\n  const nodeName = offsetParent && offsetParent.nodeName;\n\n  if (!nodeName || nodeName === 'BODY' || nodeName === 'HTML') {\n    return element ? element.ownerDocument.documentElement :...

previous.previousElementSibling\n    }\n\n    return []\n  },\n  // TODO: this is now unused; remove later along with prev()\n  next(element, selector) {\n    let next = element.nextElementSibling\n\n    while (next) {\n      if (next.matches(selector)) {\n        return [next]\n      }\n\n      next = next.nextElementSibling\n    }\n\n    return []\n  },\n\n  focusableChildren(element) {\n    const focusables = [\n      'a',\n      'button',\n      'input',\n      'textarea',\n      'select',\n   ...