Express Internationalization

A lib to perform internationalization the simple way with Express.

It's a middleware to add to your routes, with it you'll be able to translate your texts based on the Accept-Language sent.

How to use

Installation

$ npm i express-internationalization

In your main file use this way

import express from 'express';
import { internationalizationMiddleware } from 'express-internationalization';
import { resolve } from 'path';

const app = express();

app.use(
  internationalizationMiddleware({
    languagesFolderPath: resolve(__dirname, 'languages'),
    defaultLocaleToTranslate: 'pt',
  })
);

In internationalizationMiddleware there are only 2 parameters:

• languagesFolderPath: Absolute path to languages folder.
• defaultLocaleToTranslate: It is optional the default is en it is used when Accept-Language is not passed in Headers.

It is necessary to create a languages folder for example and inside it create a new folder with the desired locale and a file called translation.json which will contain all the translations for that desired language.

The structure will look like this:

├── src/
│   ├── languages/
│   │   ├── en/
│   │   │   └── translation.json
│   │   ├── pt/
│   │   │   └── translation.json

And the JSON file will contain this key and value structure:

{
  "welcomeMessage": "Hello World"
}

The key you will use in the translateByLocale function that was added in the Express request:

app.get('/', (request, response) => {
  return response.json({
    message: request.translateByLocale('welcomeMessage'),
  });
});

To change the locale according to the user's locale, the Accept-Language with the locale value must be sent in the Request Header, for example:

Accept-Language: pt

You can find a list of available locales at this Wikipedia link.