text: module.exports = function missingKeyHandler(i18next) {
    return (req, res) => {
      const { lng, ns } = req.params;
  
      if (!i18next.services.backendConnector) {
        res.statusCode = 404;
        res.end("i18next: no backend configured");
        return;
      }
  
      for (let m in req.body) {
        const v = req.body[m];
        if (i18next.options.saveMissingTo === "all") {
          i18next.options.supportedLngs
            .filter((language) => {
              return language !== "cimode";
            })
            .forEach((lng) => {
              i18next.services.backendConnector.saveMissing([lng], ns, m, v);
            });
        } else {
          i18next.services.backendConnector.saveMissing([lng], ns, m, v);
        }
      }
  
      res.end("ok");
    };
  };
  