localeLink.js

// pass location from page as props
export const localeLink = location, to => {
  const keys = ['en', 'jp']

  const { pathname } = location

  const lang = keys.find(
    k => pathname.includes(`/${k}/`) || pathname.includes(`/${k}`)
  )

  if (!lang) {
    return to
  }

  return `/${lang}${to}`
}