如何在 React 中设置 i18n 默认翻译语言

Question

I have two translations in my app using i18n translator and I'm trying with no success to set the default language.

The preferred language (the default language) will be set at registration and will come from the database.

Where can I create some kind of logic that will tell i18n what is the language coming from the backend?

The value will show something like this:

const defaultLang = currentUser.data.laiso //this will output a string eg. 'en'

The i18n configuration file looks something like this:

import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';

import Backend from 'i18next-http-backend';
import LanguageDetector from 'i18next-browser-languagedetector';

const Languages = ['en', 'de'];

i18n

  .use(Backend)

  .use(LanguageDetector)

  .use(initReactI18next)

  .init({
    fallbackLng: 'en',
    debug: true,
    whitelist: Languages,

    interpolation: {
      escapeValue: false
    }
  });


export default i18n;

Should be something written under .use(Backend) ? This is the first time using i18n so any hints would be appreciated.

This is my component where I need the translation. In it, I've tried to set the index of i18n.languages based on the language preferred, but this is not working:

import React from 'react'
import { useTranslation } from 'react-i18next';


export default function Dashboard() {
    //the logged user
    const currentUser = AuthService.getCurrentUser();
    //value from database
    const defaultLang = currentUser.data.laiso //this will output a string eg. 'en'

    //translation
    const { t, i18n } = useTranslation();

    function handleClick(lang) {
        i18n.changeLanguage(lang);
    }

    const current = i18n.languages[defaultLang === 'en' ? 0 : 1]


    return (
        <>
        <div className={styles.languageSelector}>
        <a 
          onClick={ () => handleClick('en') }
          style={{ fontWeight: current === "en" ? 800 : 400}}
        >
          EN
        </a>
        <a 
          onClick={ () => handleClick('de') }
          style={{ fontWeight: current === "de" ? 800 : 400}}
        >    
          DE
        </a>
      </div>
      <div>{t('translated.stuff')}</div>
      </>
    )
}

Answer 1

I think you need a hook to rerender the page when the language was changed. So you could add this to your Dashboard.jsx :

  React.useEffect(() => {
    const handleLanguageChange = () => {
      // Refresh your component, maybe use a hook for it.
    };

    i18next.on("languageChanged", handleLanguageChange);

    return () => {
      i18next.off("languageChanged", handleLanguageChange);
    };
  }, []);

And for the refresh logic, you could add a counter which increment when the language is changed, this should be enough to start a rerender of the component.

Answer 2

I've managed to solve this by using useEffect.

//set the language from database
  useEffect(() => {
    i18n.changeLanguage(currentUser.data.laiso);
  }, []);

That was it, Thanks

Answer 3

you can do that just by adding lng: 'en' inside.init()

.init({
    fallbackLng: 'en',
    lng: 'en', // default language
    debug: true,
    whitelist: Languages,
    interpolation: {
        escapeValue: false
    }
});

https://www.i18next.com/overview/configuration-options