app.module-update

export function appInit(i18next: ITranslationService) {
  return () =>
      i18next
      .use(i18nextXHRBackend)
      .use(i18nextLanguageDetector)
      .init({
      whitelist: ['en', 'el'],
      fallbackLng: 'en',
      debug: true,
      returnEmptyString: false,
      ns: [
        'translation'
      ],
      interpolation: {
        format: I18NextModule.interpolationFormat(defaultInterpolationFormat)
      },
      backend: {
        loadPath: 'assets/locales/{{lng}}.{{ns}}.json',
      },
      // lang detection plugin options
      detection: {
        // order and from where user language should be detected
        order: ['querystring', 'cookie'],

        // keys or params to lookup language from
        lookupCookie: 'lang',
        lookupQuerystring: 'lng',

        // cache user language on
        caches: ['localStorage', 'cookie'],

        // optional expire and domain for set cookie
        cookieMinutes: 10080, // 7 days
      }
    });
}