How to use the xregexp/xregexp-all.js.exec function in xregexp

export default async ({ store, env, route, redirect }) => {
  let publicPages = env.publicPages
  // only affect non public pages
  if (publicPages.indexOf(route.name) >= 0) {
    return true
  }

  const regX = build('^/search/hashtag/((\\pL+[\\pL0-9]*)|([0-9]+\\pL+[\\pL0-9]*))$')
  const matchHashtag = route.fullPath ? exec(decodeURI(route.fullPath), regX) : null

  if (!matchHashtag) return true

  return redirect(`/?hashtag=${encodeURI(matchHashtag[1])}`)
}

urls.forEach(url => {
    const match = exec(url, regX)
    if (match != null) {
      hashtags.push(match[1])
    }
  })
  return hashtags