next-i18next/dist/es/config/create-config.js

The easiest way to translate your NextJs apps.

import { defaultConfig } from './default-config';
import { consoleMessage, isServer } from '../utils';
const deepMergeObjects = ['backend', 'detection'];

const dedupe = names => names.filter((v, i) => names.indexOf(v) === i);

const STATIC_LOCALE_PATH = 'static/locales';
export const createConfig = userConfig => {
  if (typeof userConfig.localeSubpaths === 'string') {
    throw new Error('The localeSubpaths option has been changed to an object. Please refer to documentation.');
  }
  /*
    Initial merge of default and user-provided config
  */


  const combinedConfig = { ...defaultConfig,
    ...userConfig
  };
  /*
    Sensible defaults to prevent user duplication
  */

  combinedConfig.allLanguages = dedupe(combinedConfig.otherLanguages.concat([combinedConfig.defaultLanguage]));
  combinedConfig.whitelist = combinedConfig.allLanguages;
  const {
    allLanguages,
    defaultLanguage,
    localeExtension,
    localePath,
    localeStructure
  } = combinedConfig;

  if (isServer()) {
    const fs = eval("require('fs')");

    const path = require('path');

    let serverLocalePath = localePath;
    /*
      Validate defaultNS
      https://github.com/isaachinman/next-i18next/issues/358
    */

    if (typeof combinedConfig.defaultNS === 'string') {
      const defaultFile = `/${defaultLanguage}/${combinedConfig.defaultNS}.${localeExtension}`;
      const defaultNSPath = path.join(localePath, defaultFile);
      const defaultNSExists = fs.existsSync(defaultNSPath);

      if (!defaultNSExists) {
        /*
          If defaultNS doesn't exist, try to fall back to the deprecated static folder
          https://github.com/isaachinman/next-i18next/issues/523
        */
        const staticDirPath = path.resolve(process.cwd(), STATIC_LOCALE_PATH, defaultFile);
        const staticDirExists = fs.existsSync(staticDirPath);

        if (staticDirExists) {
          consoleMessage('warn', 'next-i18next: Falling back to /static folder, deprecated in next@9.1.*', combinedConfig);
          serverLocalePath = STATIC_LOCALE_PATH;
        } else if (process.env.NODE_ENV !== 'production') {
          throw new Error(`Default namespace not found at ${defaultNSPath}`);
        }
      }
    }
    /*
      Set server side backend
    */


    combinedConfig.backend = {
      loadPath: path.resolve(process.cwd(), `${serverLocalePath}/${localeStructure}.${localeExtension}`),
      addPath: path.resolve(process.cwd(), `${serverLocalePath}/${localeStructure}.missing.${localeExtension}`)
    };
    /*
      Set server side preload (languages and namespaces)
    */

    combinedConfig.preload = allLanguages;

    if (!combinedConfig.ns) {
      const getAllNamespaces = p => fs.readdirSync(p).map(file => file.replace(`.${localeExtension}`, ''));

      combinedConfig.ns = getAllNamespaces(path.resolve(process.cwd(), `${serverLocalePath}/${defaultLanguage}`));
    }
  } else {
    let clientLocalePath = localePath;
    /*
      Remove public prefix from client site config
    */

    if (localePath.startsWith('/public/')) {
      clientLocalePath = localePath.replace(/^\/public/, '');
    }
    /*
      Set client side backend
    */


    combinedConfig.backend = {
      loadPath: `${clientLocalePath}/${localeStructure}.${localeExtension}`,
      addPath: `${clientLocalePath}/${localeStructure}.missing.${localeExtension}`
    };
    combinedConfig.ns = [combinedConfig.defaultNS];
  }
  /*
    Set fallback language to defaultLanguage in production
  */


  if (!userConfig.fallbackLng) {
    combinedConfig.fallbackLng = process.env.NODE_ENV === 'production' ? combinedConfig.defaultLanguage : false;
  }
  /*
    Deep merge with overwrite - goes last
  */


  deepMergeObjects.forEach(obj => {
    if (userConfig[obj]) {
      combinedConfig[obj] = { ...defaultConfig[obj],
        ...userConfig[obj]
      };
    }
  });
  return combinedConfig;
};