fastify-i18n-plugin

A Fastify plugin that adds dynamic internationalization (i18n) to your Fastify project. This plugin allows you to load translations dynamically from JSON files and serve translated content based on the user's locale.

Installation

You can install the plugin via npm:

npm install fastify-i18n-plugin

Usage

Here's an example of how to register the plugin in your Fastify project:

import Fastify from 'fastify';
import i18nPlugin from 'fastify-i18n-plugin';

const fastify = Fastify({
  logger: true,
});

// Register the i18n plugin
fastify.register(i18nPlugin, {
  defaultLocale: 'en',
  directory: './translations',
});

// Define some routes
fastify.get('/:lang/greet', async (request, reply) => {
  const lang = request.params.lang;
  const greeting = request.i18n(lang).greeting;
  reply.send({ greeting });
});

// Start the server
fastify.listen({ port: 3000 }, (err, address) => {
  if (err) {
    fastify.log.error(err);
    process.exit(1);
  }
  fastify.log.info(`Server listening at ${address}`);
});

Features

• Dynamic Translations: Load translations from JSON files in a specified directory.
• Route-based Language Switching: The language is determined based on the route parameter (:lang).
• Caching for Performance: Caching of translation files for improved performance.
• Supports Multiple Languages: Easily add support for multiple languages by adding JSON translation files.

Example Route

The following route will respond with a greeting in the requested language:

• GET /en/greet: Responds with the greeting in English.
• GET /it/greet: Responds with the greeting in Italian.

Example Response:

{
  "greeting": "Hello"  // For English
}

Or:

{
  "greeting": "Ciao"  // For Italian
}

Translation Files

You can add translation files in the translations folder like this:

// translations/en.json
{
  "greeting": "Hello",
  "farewell": "Goodbye"
}

// translations/it.json
{
  "greeting": "Ciao",
  "farewell": "Arrivederci"
}

Adding New Languages

To add support for a new language, simply create a new JSON file in the translations directory and include the necessary translations. For example, to add French:

// translations/fr.json
{
  "greeting": "Bonjour",
  "farewell": "Au revoir"
}

Contributing

If you would like to contribute or suggest new features, feel free to open a pull request or create an issue on the project's GitHub repository.

License

This project is licensed under the ISC License.