Как правильно сделать маршрутизацию для локализации на Node.js и Express.js?

const langs = ['en', 'ru', 'de', 'fr'];
const langsRE = new RegExp(`/(${langs.join('|')})(?:/|$)`, 'i');

app.set('view engine', 'pug');

const router = express.Router();
router.get('/', (req, res) => {
  res.render('index', res.locals);
});
router.get('/about', (req, res) => {
  res.render('about', res.locals);
});

app.use((req, res, next) => {
  let lang = 'en';
  const found = langsRE.exec(req.url);
  if (found) {
    lang = found[1];
    req.url = req.url.replace(langsRE, '/');
  }
  Object.assign(res.locals, {lang, __: app.locales[lang]});
  next();
});
app.use(router);