network-resurrector-frontend/src/utils/i18n.js

import i18n from "i18next";
import { initReactI18next } from "react-i18next";
import Backend from "i18next-http-backend";
import LanguageDetector from "i18next-browser-languagedetector";
import moment from "moment";
import "moment/locale/ro.js";
import "moment/locale/de.js";

i18n
  .use(Backend)
  .use(LanguageDetector)
  .use(initReactI18next) // passes i18n down to react-i18next
  .init(
    {
      fallbackLng: "en",
      debug: true,
      ns: ["translations"],
      defaultNS: "translations",
      //whitelist: ["en", "ro"],
      interpolation: {
        escapeValue: false, // not needed for react as it escapes by default
        format: function (value, format, lng) {
          if (format === "uppercase") return value.toUpperCase();
          if (format === "intlDate") {
            if (value && moment(value).isValid()) {
              return moment(value).format("L");
            }
            return "";
          }

          if (format === "intlLongDate") {
            if (value && moment(value).isValid()) {
              return moment(value).format("LLLL");
            }
            return "";
          }

          if (format === "intlTimeFromX") {
            if (value && moment(value.start).isValid()) {
              let startDate = moment(value.start);
              let endDate = moment(value.end);
              return moment(endDate).from(startDate, true);
            }
            return "";
          }

          if (format === "intlHoursFromX") {
            if (value && moment(value.start).isValid()) {
              let startDate = moment(value.start);
              let endDate = moment(value.end);
              let span = moment.duration(endDate - startDate);
              return `${parseInt(span.asHours(), 10)}h ${parseInt(
                span.asMinutes() % 60,
                10
              )}m`;
            }
            return "";
          }

          if (format === "intlNumber")
            return new Intl.NumberFormat(lng).format(value);
          if (format === "intlDecimal")
            return new Intl.NumberFormat(lng, {
              minimumFractionDigits: 2
            }).format(value);
          if (format === "intlDecimal2")
            return new Intl.NumberFormat(lng, {
              minimumFractionDigits: 2,
              maximumFractionDigits: 2
            }).format(value);

          //dateformat
          if (value && value.format) {
            if (value.value && moment(value).isValid()) {
              return moment(value.value).format(value.format);
            }
            return "";
          }

          return value;
        }
      },
      backend: {
        loadPath: `${process.env.PUBLIC_URL || ""}/locales/{{lng}}/{{ns}}.json`
      }
    },
    () => {
      const currentLang = i18n.language;
      if (!currentLang || !currentLang.startsWith("ro")) {
        i18n.changeLanguage("en");
      } else {
        i18n.changeLanguage("ro");
      }
    }
  );

i18n.on("languageChanged", function (lng) {
  moment.locale(lng);
});

export default i18n;