next-intl-split

About

A loader for next-intl to split translation files properly inside a Next.js app. Using next-intl-split you can separate your translations for maintaining purposes while the package automatically merges the content into a single translation object.

Table of Contents

• Installation
• What about next-intl built-in split approach?
• How to use the package?
• How to add types?

Installation

Run the following command to install the package:

npm i next-intl-split

Note: You need to have the next.js and next-intl installed to make the next-intl-split work as expected.

What about next-intl built-in split approach?

The approach provided by next-intl itself can be convincing but as it puts everything together, you may end up with duplicated names or very long key names for your translation strings. So in some cases, this can be its cons:

• Long prefixes for a name to avoid conflicts like homeHeroMainButtonTitle
• You may not be able to use the namespace approach properly.

On the other hand next-intl-split is a tiny package (just a few utilities to help you) that lets you have a cleaner way of managing your translations and not worry about naming conflicts.

• No need to worry about the prefixes as they will automatically be prefixed by the parent's folder name. You split your files and you can have something like this home.hero.button.main
• Have the namespace approach. Using the namespace the above name could be like button.main
• Split translations freely, without worrying about hardcoding the file names in the getRequestConfig utility.
• Smaller JSON files.
• Cleaner JSON files.
• Support for TypeScript.
• Support for Next.Js Config file with .ts/.js/.mjs extensions.

How to use the package?

If you're going to deploy to a serverless deployment environment like Vercel, you need to do some extra stuff that is mentioned.

• Edit the next.config.js to use the plugin from next-intl-split rather that next-intl
• Edit the getRequestConfig file to conditionally load translations based on production or development environments.
• Build once before deployment

With that in mind, after installing the package:

Step One

In your desired path, create your dictionaries (or whatever you name that). It is important to name the translation files index.json

Example view of translation files:

// /src/i18n
└── dictionaries
    // English
    ├── en
    |   ├── shared
    |   |   └── header
    |   |       └── index.json
    |   ├── home
    |   |   ├── hero
    |   |   |   └── index.json
    |   |   └── featured
    |   |       └── index.json
    |   └── about
    |       └── hero
    |           └── index.json
    // Spanish
    ├── es
    |   ├── shared
    |   |   └── header
    |   |       └── index.json
    |   ├── home
    |   |   ├── hero
    |   |   |   └── index.json
    |   |   └── featured
    |   |       └── index.json
    |   └── about
    |       └── hero
    |           └── index.json
    // Persian
    └── fa
        ├── shared
        |   └── header
        |       └── index.json
        ├── home
        |   ├── hero
        |   |   └── index.json
        |   └── featured
        |       └── index.json
        └── about
            └── hero
                └── index.json

Step Two

App Router

Next Config (Only for serverless deployment environments)

Use next-intl-split plugin instead of the next-intl one.

const createNextIntlSplitPlugin = require('next-intl-split/plugin');
// import createNextIntlSplitPlugin from 'next-intl-split/plugin'; // For .mjs

const withNextIntlSplitPlugin = createNextIntlSplitPlugin(
  './src/core/i18n/dictionaries', // REQUIRED relative path to dictionaries folder starting from src folder.
  './src/core/i18n/request.ts' // OPTIONAL Relative path if you've changed the next-intl request module path.
);

/** @type {import('next').NextConfig} */
const nextConfig = {};

module.exports = withNextIntlSplitPlugin(nextConfig);
// export default withNextIntlSplit(nextConfig); // For .mjs

This plugin will merge the messages into a single file at the build time.

Request Config (Non serverless environment)

In the getRequestConfig function, wrap the messages object with loadI18nTranslations utility.

• With i18n routing

import { notFound } from 'next/navigation';
import { getRequestConfig } from 'next-intl/server';
import { loadI18nTranslations } from 'next-intl-split/load';

// Can be imported from a shared config
const locales = ['en', 'es', 'fa'];

export default getRequestConfig(async ({ locale }) => {
  // Validate that the incoming `locale` parameter is valid
  if (!locales.includes(locale as any)) notFound();

  // The provided route should starts from the src folder with the Relative approach.
  const messages = loadI18nTranslations('./src/i18n/dictionaries/', locale);

  return {
    messages,
  };
});

• Without i18n routing

import { getRequestConfig } from 'next-intl/server';
import { loadI18nTranslations } from 'next-intl-split/load';

export default getRequestConfig(async () => {
  const locale = 'en';

  // The provided route should starts from the src folder with the Relative approach.
  const messages = loadI18nTranslations('./src/i18n/dictionaries/', locale);

  return {
    locale,
    messages,
  };
});

Request Config (Serverless environment like VERCEL)

In the getRequestConfig function:

• With i18n routing

import { notFound } from 'next/navigation';
import { getRequestConfig } from 'next-intl/server';
import { loadI18nTranslations } from 'next-intl-split/load';

// Can be imported from a shared config
const locales = ['en', 'es', 'fa'];

export default getRequestConfig(async ({ locale }) => {
  // Validate that the incoming `locale` parameter is valid
  if (!locales.includes(locale as any)) notFound();

  // The relative path to the dictionaries folder
  let messages = (await import(`./dictionaries/${locale}.json`)).default;

  if (process.env.NODE_ENV === 'development') {
    // The provided route should starts from the src folder with the Relative approach.
    messages = loadI18nTranslations('./src/i18n/dictionaries', locale);
  }

  return {
    messages,
  };
});

• Without i18n routing

import { getRequestConfig } from 'next-intl/server';
import { loadI18nTranslations } from 'next-intl-split/load';

export default getRequestConfig(async () => {
  const locale = 'en';

  // The relative path to the dictionaries folder
  let messages = (await import(`./dictionaries/${locale}.json`)).default;

  if (process.env.NODE_ENV === 'development') {
    // The provided route should starts from the src folder with the Relative approach.
    messages = loadI18nTranslations('./src/i18n/dictionaries', locale);
  }

  return {
    locale,
    messages,
  };
});

Pages Router

In the getStaticProps function, wrap the messages object with loadI18nTranslations utility.

// ...
export async function getStaticProps(context) {
  // The provided route should starts from the src folder with the Relative approach.
  const messages = loadI18nTranslations(
    './src/i18n/dictionaries/',
    context.locale
  );

  return {
    props: {
      messages,
    },
  };
}

Add Support for TypeScript

Starting from v1.2.4 you'll be able to enable type check.

1. Add global type declaration as mentioned in next-intl documentation. Check this

2. Based on your default locale, ensure that there is a .json file for that in your messages (or translations) folder. As an example if your default locale is en and you have your messages in ./src/messages/, make sure there is an en.json module in it, even an empty one or you can build your project once to have them merged automatically.

3. Inside the getRequestConfig, add the true parameters to the loadI18nTranslations utitlity as the 3rd param.

// ./src/i18n/request.ts
...
export default getRequestConfig(async ({ locale }) => {
  ...

  messages = loadI18nTranslations(
    './src/messages',
    locale,
    true // This will enable type check
  );

  ...
});
...