We can now use karax/languages from the native backend

[planetis-m]

There is no reason not to share the Language enum between backend and frontend. With this change this is possible. You can have something like this in your server:

const
  defaultLanguage = Language.enUS

proc parseLanguage(s: string): Language =
  let i = binarySearch(languageToCode, s)
  if i >= 0: result = Language(i)
  else: result = defaultLanguage

proc getLanguage(url: Uri): Language =
  var lang = ""
  for key, val in decodeQuery(url.query):
    if key == "lang":
      lang = val
      break
  result = parseLanguage(lang)

The lang=key is send from the frontend like this:

 ajaxGet("/route?lang=" & languageToCode[getCurrentLanguage()],
                  {cstring"Accept": cstring"application/json"}, onRoute)