react-i18next/src/context.js

Internationalization for react done right. Using the i18next i18n ecosystem.

import { createContext } from 'react';
import { getDefaults, setDefaults } from './defaults.js';
import { getI18n, setI18n } from './i18nInstance.js';
import { initReactI18next } from './initReactI18next.js';

export { getDefaults, setDefaults, getI18n, setI18n, initReactI18next };

export const I18nContext = createContext();

export class ReportNamespaces {
  constructor() {
    this.usedNamespaces = {};
  }

  addUsedNamespaces(namespaces) {
    namespaces.forEach((ns) => {
      if (!this.usedNamespaces[ns]) this.usedNamespaces[ns] = true;
    });
  }

  getUsedNamespaces() {
    return Object.keys(this.usedNamespaces);
  }
}

export const composeInitialProps = (ForComponent) => async (ctx) => {
  const componentsInitialProps = (await ForComponent.getInitialProps?.(ctx)) ?? {};

  const i18nInitialProps = getInitialProps();

  return {
    ...componentsInitialProps,
    ...i18nInitialProps,
  };
};

export const getInitialProps = () => {
  const i18n = getI18n();
  const namespaces = i18n.reportNamespaces?.getUsedNamespaces() ?? [];

  const ret = {};
  const initialI18nStore = {};
  i18n.languages.forEach((l) => {
    initialI18nStore[l] = {};
    namespaces.forEach((ns) => {
      initialI18nStore[l][ns] = i18n.getResourceBundle(l, ns) || {};
    });
  });

  ret.initialI18nStore = initialI18nStore;
  ret.initialLanguage = i18n.language;

  return ret;
};