gatsby-plugin-react-i18next

gatsby-plugin-react-i18next

Easily translate your Gatsby website into multiple languages.

Features

• Seamless integration with react-i18next - a powerful internationalization framework for React.
• Code splitting. Load translations for each page separately.
• Automatic redirection based on the user's preferred language in browser provided by browser-lang.
• Support multi-language url routes in a single page component. You don't have to create separate pages such as pages/en/index.js or pages/es/index.js.
• SEO friendly
• Support for gatsby-plugin-layout

Why?

When you build multilingual sites, Google recommends using different URLs for each language version of a page rather than using cookies or browser settings to adjust the content language on the page. (read more)

:boom: Breaking change since v2.0.0

As of V2.0.0, this plugin only supports Gatsby 4.16.0+ and React 18+.

:boom: Breaking change since v1.0.0

As of v1.0.0, language JSON resources should be loaded by gatsby-source-filesystem plugin and then fetched by GraphQL query. It enables incremental build and hot-reload as language JSON files change.

Users who have loaded language JSON files using path option will be affected. Please check configuration example on below.

Demo

• View demo online
• Source code

Used by

• monei.com - The digital payment gateway with best rates.
• moonmail.io - OmniChannel Communication Platform used by more than 100,000 businesses worldwide.
• nyxo.app – Sleep tracking and coaching (source code)

Tutorials

• Best internationalization for Gatsby by Adriano Raiano

How to use

Install package

yarn add gatsby-plugin-react-i18next i18next react-i18next

or

npm install --save gatsby-plugin-react-i18next i18next react-i18next

Configure the plugin

// In your gatsby-config.js
plugins: [
  {
    resolve: `gatsby-source-filesystem`,
    options: {
      path: `${__dirname}/locales`,
      name: `locale`
    }
  },
  {
    resolve: `gatsby-plugin-react-i18next`,
    options: {
      localeJsonSourceName: `locale`, // name given to `gatsby-source-filesystem` plugin.
      languages: [`en`, `es`, `de`],
      defaultLanguage: `en`,
      siteUrl: `https://example.com`,
      // if you are using trailingSlash gatsby config include it here, as well (the default is 'always')
      trailingSlash: 'always',
      // you can pass any i18next options
      i18nextOptions: {
        interpolation: {
          escapeValue: false // not needed for react as it escapes by default
        },
        keySeparator: false,
        nsSeparator: false
      },
      pages: [
        {
          matchPath: '/:lang?/blog/:uid',
          getLanguageFromPath: true,
          excludeLanguages: ['es']
        },
        {
          matchPath: '/preview',
          languages: ['en']
        }
      ]
    }
  }
];

This example is not using semantic keys instead the entire message will be used as a key. Read more.

NOTE: If you want nested translation keys do not set keySeparator: false. More configuration options.

You'll also need to add language JSON resources to the project.

For example,

language resource files	language
/locales/en/index.json	English
/locales/es/index.json	Spanish
/locales/de/index.json	German

You can use different namespaces to organize your translations. Use the following file structure:

|-- language
   |-- namespace.json

For example:

|-- en
    |-- common.json
    |-- index.json

The default namespace is translation. Read more about i18next namespaces

Change your components

Use react i18next useTranslation react hook and Trans component to translate your pages.

gatsby-plugin-react-i18next exposes all react-i18next methods and components.

Replace Gatsby Link component with the Link component exported from gatsby-plugin-react-i18next

import {graphql} from 'gatsby';
import React from 'react';
import {Link, Trans, useTranslation} from 'gatsby-plugin-react-i18next';
import Layout from '../components/layout';
import Image from '../components/image';
import SEO from '../components/seo';

const IndexPage = () => {
  const {t} = useTranslation();
  return (
    <Layout>
      <SEO title={t('Home')} />
      <h1>
        <Trans>Hi people</Trans>
      </h1>
      <p>
        <Trans>Welcome to your new Gatsby site.</Trans>
      </p>
      <p>
        <Trans>Now go build something great.</Trans>
      </p>
      <div style={{maxWidth: `300px`, marginBottom: `1.45rem`}}>
        <Image />
      </div>
      <Link to="/page-2/">
        <Trans>Go to page 2</Trans>
      </Link>
    </Layout>
  );
};

export default IndexPage;

export const query = graphql`
  query ($language: String!) {
    locales: allLocale(filter: {language: {eq: $language}}) {
      edges {
        node {
          ns
          data
          language
        }
      }
    }
  }
`;

and in locales/en/translations.json you will have

{
  "Home": "Home",
  "Hi people": "Hi people",
  "Welcome to your new Gatsby site.": "Welcome to your new Gatsby site.",
  "Now go build something great.": "Now go build something great.",
  "Go to page 2": "Go to page 2"
}

This example is not using semantic keys instead the entire message will be used as a key. Read more.

Changing the language

gatsby-plugin-react-i18next exposes useI18next hook

import {Link, useI18next} from 'gatsby-plugin-react-i18next';
import React from 'react';

const Header = ({siteTitle}) => {
  const {languages, changeLanguage} = useI18next();
  return (
    <header className="main-header">
      <h1 style={{margin: 0}}>
        <Link
          to="/"
          style={{
            color: `white`,
            textDecoration: `none`
          }}>
          {siteTitle}
        </Link>
      </h1>
      <ul className="languages">
        {languages.map((lng) => (
          <li key={lng}>
            <a
              href="#"
              onClick={(e) => {
                e.preventDefault();
                changeLanguage(lng);
              }}>
              {lng}
            </a>
          </li>
        ))}
      </ul>
    </header>
  );
};

Or a more SEO friendly version using Link component

import {Link, useI18next} from 'gatsby-plugin-react-i18next';
import PropTypes from 'prop-types';
import React from 'react';

const Header = ({siteTitle}) => {
  const {languages, originalPath} = useI18next();
  return (
    <header className="main-header">
      <h1 style={{margin: 0}}>
        <Link
          to="/"
          style={{
            color: `white`,
            textDecoration: `none`
          }}>
          {siteTitle}
        </Link>
      </h1>
      <ul className="languages">
        {languages.map((lng) => (
          <li key={lng}>
            <Link to={originalPath} language={lng}>
              {lng}
            </Link>
          </li>
        ))}
      </ul>
    </header>
  );
};

Plugin Options

Option	Type	Description
localeJsonSourceName	string	name of JSON translation file nodes that are loaded by gatsby-source-filesystem (set by option.name). Default is locale
localeJsonNodeName	string	name of GraphQL node that holds locale data. Default is locales
languages	string[]	supported language keys
defaultLanguage	string	default language when visiting /page instead of /es/page
fallbackLanguage	string	optionally fallback to a different language than the defaultLanguage
generateDefaultLanguagePage	boolean	generate dedicated page for default language. e.g) /en/page. It is useful when you need page urls for all languages. For example, server-side redirect using Accept-Language header. Default is false.
redirect	boolean	if the value is true, / or /page-2 will be redirected to the user's preferred language router. e.g) /es or /es/page-2. Otherwise, the pages will render defaultLangugage language. Default is true
siteUrl	string	public site url, is used to generate language specific meta tags
pages	array	an array of page options used to modify plugin behaviour for specific pages
i18nextOptions	object	i18next configuration options
verbose	boolean	Verbose output. Default is true

Page options

Option	Type	Description
matchPath	string	a path pattern like /:lang?/blog/:uid, check path-to-regexp for more info
getLanguageFromPath	boolean	if set to true the language will be taken from the :lang param in the path instead of automatically generating a new page for each language
excludeLanguages	array	an array of languages to exclude, if specified the plugin will not automatically generate pages for those languages, this option can be used to replace pages in some languages with custom ones
languages	array	an array of languages, if specified the plugin will automatically generate pages only for those languages

Plugin API

Link

Link component is identical to Gatsby Link component except that you can provide additional language prop to create a link to a page with different language

import {Link} from 'gatsby-plugin-react-i18next';

const SpanishAboutLink = () => (
  <Link to="/about" language="es">
    About page in Spanish
  </Link>
);

I18nextContext

Use this react context to access language information about the page

const context = React.useContext(I18nextContext);

Content of the context object

Attribute	Type	Description
language	string	current language
languages	string[]	supported language keys
routed	boolean	if false it means that the page is in default language
defaultLanguage	string	default language provided in plugin options
originalPath	string	page path in default language
path	string	page path
siteUrl	string	public site url provided in plugin options

The same context will be also available in the Gatsby pageContext.i18n object

useI18next

This react hook returns I18nextContext, object and additional helper functions

Function	Description
navigate	This is a wrapper around Gatsby navigate helper function that will navigate to the page in selected language
changeLanguage	A helper function to change language. The first parameter is a language code. Signature: (language: string, to?: string, options?: NavigateOptions) => Promise<void>. You can pass additional parameters to navigate to different page.

useI18next also exposes the output of react i18next useTranslation so you can use

const {t} = useI18next();

How to exclude pages that already have language key in path

For example if you have some other plugin or script that generates your blog posts from headless CRM like prismic.io in different languages you would like to exclude those pages, to not generate duplicates for each language key. You can do that by providing pages option.

pages: [
  {
    matchPath: '/:lang?/blog/:uid',
    getLanguageFromPath: true,
    excludeLanguages: ['es']
  }
];

You have to specify a :lang url param, so the plugin knows what part of the path should be treated as language key. In this example the plugin will automatically generate language pages for all languages except es. Assuming that you have ['en', 'es', 'de'] languages the blog post with the path /blog/hello-world you will have the following pages generated:

• /blog/hello-world - the English version (if you have en as a defaultLanguage)
• /es/blog/hello-world - the Spanish version that should exist before you run the plugin (created manually or at build time with a plugin or api call)
• /de/blog/hello-world - the German version that is generated automatically

Omit excludeLanguages to get all the languages form the path. Make sure that you have pages for all the languages that you specify in the plugin, otherwise you might have broken links.

You may also need to add a pages config for the 404 page, if it uses the same path pattern as your excluded pages. Note that the order of these rules is important.

pages: [
  {
    matchPath: '/:lang?/404',
    getLanguageFromPath: false
  },
  {
    matchPath: '/:lang?/:uid',
    getLanguageFromPath: true,
    excludeLanguages: ['es']
  }
];

How to exclude a page that should not be translated

You can limit the languages used to generate versions of a specific page, for example to limit /preview page to only English version:

pages: [
  {
    matchPath: '/preview',
    languages: ['en']
  }
];

How to fetch translations of specific namespaces only

You can use ns and language field in gatsby page queries to fetch specific namespaces that are being used in the page. This will be useful when you have several big pages with lots of translations.

export const query = graphql`
  query ($language: String!) {
    locales: allLocale(filter: {ns: {in: ["common", "index"]}, language: {eq: $language}}) {
      edges {
        node {
          ns
          data
          language
        }
      }
    }
  }
`;

Note that in this case only files common.json and index.json will be loaded. This plugin will automatically add all loaded namespaces as fallback namespaces so if you don't specify a namespace in your translations they will still work.

How to fetch language specific data

You can use language variable in gatsby page queries to fetch additional data for each language. For example if you're using gatsby-transformer-json your query might look like:

export const query = graphql`
  query ($language: String!) {
    dataJson(language: {eq: $language}) {
      ...DataFragment
    }
  }
`;

How to add sitemap.xml for all language specific pages

You can use gatsby-plugin-sitemap to automatically generate a sitemap during build time. You need to customize query to fetch only original pages and then serialize data to build a sitemap. Here is an example:

// In your gatsby-config.js
plugins: [
  {
    resolve: 'gatsby-plugin-sitemap',
    options: {
      excludes: ['/**/404', '/**/404.html'],
      query: `
          {
            site {
              siteMetadata {
                siteUrl
              }
            }
            allSitePage(filter: {context: {i18n: {routed: {eq: false}}}}) {
              edges {
                node {
                  context {
                    i18n {
                      defaultLanguage
                      languages
                      originalPath
                    }
                  }
                  path
                }
              }
            }
          }
        `,
      serialize: ({site, allSitePage}) => {
        return allSitePage.edges.map((edge) => {
          const {languages, originalPath, defaultLanguage} = edge.node.context.i18n;
          const {siteUrl} = site.siteMetadata;
          const url = siteUrl + originalPath;
          const links = [
            {lang: defaultLanguage, url},
            {lang: 'x-default', url}
          ];
          languages.forEach((lang) => {
            if (lang === defaultLanguage) return;
            links.push({lang, url: `${siteUrl}/${lang}${originalPath}`});
          });
          return {
            url,
            changefreq: 'daily',
            priority: originalPath === '/' ? 1.0 : 0.7,
            links
          };
        });
      }
    }
  }
];

How to use a fallback language with semantic keys (vs. message strings)

By default this plugin is setup to fallback on the entire message string, that is used as language key.

In order to use semantic keys, so the fallback message string is the default's language value (instead of the key), it is possible to do the following;

In /gatsby-config.js, setup the plugin as usual, and add the key options.i18nextOptions.fallbackLng (i18next documentation, configuration options, and fallback options);

{
    resolve: `gatsby-plugin-react-i18next`,
    options: {
        localeJsonSourceName: `locale`,
        languages: [`en`, `de`, `fr`],
        defaultLanguage: `en`,
        siteUrl: `https://example.com/`,
        i18nextOptions: {
            fallbackLng: 'en', // here we provide the fallback language to i18next
            interpolation: {
                escapeValue: false
            },
            keySeparator: false,
            nsSeparator: false
        }
    }
}

Then in a page query, we avoid to specify a $language variable used as filter, so i18next gets access to the available locales, used as fallback.

// /pages/index.js
export const query = graphql`
  query { // no $language variable defined, no filters on allLocale
    locales: allLocale {
      edges {
        node {
          ns
          data
          language
        }
      }
    }
  }
`;

How to extract translations from pages

You can use babel-plugin-i18next-extract automatically extract translations inside t function and Trans component from you pages and save them in JSON.

1. Install

yarn add @babel/cli @babel/plugin-transform-typescript babel-plugin-i18next-extract -D

1. create babel-extract.config.js file (don't name it babel.config.js, or it will be used by gatsby)

module.exports = {
  presets: ['babel-preset-gatsby'],
  plugins: [
    [
      'i18next-extract',
      {
        keySeparator: null,
        nsSeparator: null,
        keyAsDefaultValue: ['en'],
        useI18nextDefaultValue: ['en'],
        discardOldKeys: true,
        outputPath: 'locales/{{locale}}/{{ns}}.json',
        customTransComponents: [['gatsby-plugin-react-i18next', 'Trans']]
      }
    ]
  ],
  overrides: [
    {
      test: [`**/*.ts`, `**/*.tsx`],
      plugins: [[`@babel/plugin-transform-typescript`, {isTSX: true}]]
    }
  ]
};

1. add a script to your package.json

{
  "scripts": {
    "extract": "yarn run babel --config-file ./babel-extract.config.js -o tmp/chunk.js 'src/**/*.{js,jsx,ts,tsx}' && rm -rf tmp"
  }
}

If you want to extract translations per page, you can add a special comment at the beginning of the page:

// i18next-extract-mark-ns-start about-page

This will create a file about-page.json with all the translations on this page.

To load this file you need to specify a namespace like this:

export const query = graphql`
  query ($language: String!) {
    locales: allLocale(
      filter: {ns: {in: ["translation", "about-page"]}, language: {eq: $language}}
    ) {
      edges {
        node {
          ns
          data
          language
        }
      }
    }
  }
`;

Automatically translate to different languages

After your messages had been extracted you can use AWS Translate to automatically translate messages to different languages.

This functionality is out of the scope of this plugin, but you can get the idea from this script.

How to fallback to a different language than the defaultLanguage

By default, on first load, this plugin will fallback to the defaultLanguage if the browser's detected language is not included in the array of languages.

If you want to fallback to a different language in the languages array, you can set the fallbackLanguage option.

For example, if the default language of your site is Japanese, you only have English as another language, and you want all other browser-detected languages to fallback to English, not Japanese.

module.exports = {
  plugins: [
    {
      resolve: 'gatsby-plugin-react-i18next',
      options: {
        defaultLanguage: 'ja',
        fallbackLanguage: 'en'
      }
    }
  ]
};

Mentions

• Best internationalization for Gatsby by Adriano Raiano

Credits

This package is based on:

• gatsby-plugin-intl by Daewoong Moon
• gatsby-i18n-plugin by ikhudo

License

MIT © microapps