next-i18next/dist/es/serverSideTranslations.js

The easiest way to translate your NextJs apps.

import fs from 'fs';
import path from 'path';
import { createConfig } from './config/createConfig';
import createClient from './createClient/node';
import { globalI18n } from './appWithTranslation';
import { getFallbackForLng, unique } from './utils';
let DEFAULT_CONFIG_PATH = './next-i18next.config.js';

/**
 * One line expression like `const { I18NEXT_DEFAULT_CONFIG_PATH: DEFAULT_CONFIG_PATH = './next-i18next.config.js' } = process.env;`
 * is breaking the build, so keep it like this.
 *
 * @see https://github.com/i18next/next-i18next/pull/2084#issuecomment-1420511358
 */
if (process.env.I18NEXT_DEFAULT_CONFIG_PATH) {
  DEFAULT_CONFIG_PATH = process.env.I18NEXT_DEFAULT_CONFIG_PATH;
}
export const serverSideTranslations = async (initialLocale, namespacesRequired = undefined, configOverride = null, extraLocales = false) => {
  if (typeof initialLocale !== 'string') {
    throw new Error('Initial locale argument was not passed into serverSideTranslations');
  }
  let userConfig = configOverride;
  const configPath = path.resolve(DEFAULT_CONFIG_PATH);
  if (!userConfig && fs.existsSync(configPath)) {
    userConfig = await import(configPath);
  }
  if (userConfig === null) {
    throw new Error(`next-i18next was unable to find a user config at ${configPath}`);
  }
  const config = createConfig({
    ...userConfig,
    lng: initialLocale
  });
  const {
    localeExtension,
    localePath,
    fallbackLng,
    reloadOnPrerender
  } = config;
  if (reloadOnPrerender) {
    await globalI18n?.reloadResources();
  }
  const {
    i18n,
    initPromise
  } = createClient({
    ...config,
    lng: initialLocale
  });
  await initPromise;
  const hasCustomBackend = userConfig?.use?.some(b => b.type === 'backend');
  if (hasCustomBackend && namespacesRequired) {
    await i18n.loadNamespaces(Array.isArray(namespacesRequired) ? namespacesRequired : namespacesRequired);
  }
  const initialI18nStore = {
    [initialLocale]: {}
  };
  getFallbackForLng(initialLocale, fallbackLng ?? false).concat(extraLocales || []).forEach(lng => {
    initialI18nStore[lng] = {};
  });
  if (!Array.isArray(namespacesRequired)) {
    if (typeof localePath === 'function') {
      throw new Error('Must provide namespacesRequired to serverSideTranslations when using a function as localePath');
    }
    const getLocaleNamespaces = path => fs.existsSync(path) ? fs.readdirSync(path).map(file => file.replace(`.${localeExtension}`, '')) : [];
    const namespacesByLocale = Object.keys(initialI18nStore).map(locale => getLocaleNamespaces(path.resolve(process.cwd(), `${localePath}/${locale}`))).flat();
    namespacesRequired = unique(namespacesByLocale);
  }
  namespacesRequired.forEach(ns => {
    for (const locale in initialI18nStore) {
      initialI18nStore[locale][ns] = (i18n.services.resourceStore.data[locale] || {})[ns] || {};
    }
  });
  return {
    _nextI18Next: {
      initialI18nStore,
      initialLocale,
      ns: namespacesRequired,
      userConfig: config.serializeConfig ? userConfig : null
    }
  };
};