qapp-core/src/hooks/useIframe.tsx

import { useEffect } from 'react';
import { supportedLanguages } from '../i18n/i18n';
import i18n from '../i18n/i18n';
type Language = 'de' | 'en' | 'es' | 'fr' | 'it' | 'ja' | 'ru' | 'zh';
type Theme = 'dark' | 'light';

interface CustomWindow extends Window {
  _qdnTheme: Theme;
  _qdnLang: Language;
}
const customWindow = window as unknown as CustomWindow;

export const useIframe = () => {
  useEffect(() => {
    const languageDefault = customWindow?._qdnLang;

    if (supportedLanguages?.includes(languageDefault)) {
      i18n.changeLanguage(languageDefault);
    }

    function handleNavigation(event: {
      data: {
        action: string;
        language: Language;
      };
    }) {
      if (event.data?.action === 'LANGUAGE_CHANGED' && event.data.language) {
        if (!supportedLanguages?.includes(event.data.language)) return;

        i18n.changeLanguage(event.data.language);
      }
    }

    window.addEventListener('message', handleNavigation);

    return () => {
      window.removeEventListener('message', handleNavigation);
    };
  }, []);
  return;
};