Lingua is a middleware for the Express.js framework that helps you to internationalise your webapp easily. It determines the language of the user agent and pushes the i18n resources to your views.

$ npm install lingua

Using lingua comes down with four simple steps:

1. Grab lingua

   var express = require('express'),
       lingua  = require('lingua');
   
   ...
   // Express init code goes here
   ...    
   
   // Express app configuration code and lingua init.
   app.configure(function(){
       ...
       app.register(".html", require("jqtpl").express);
       app.set('views', __dirname + '/views');
       app.set("view engine", "html");
   
       // Lingua configuration
       app.use(lingua(app, {
           defaultLocale: 'en',
           path: __dirname + '/i18n'
       }));
   
       app.use(express.bodyParser());
       app.use(express.methodOverride());
       app.use(express.static(__dirname + '/public'));
       app.use(app.router);
   
       ...
   });

   Note: Please ensure that the call: "app.use(app.router);" is the last entry in your configuration section.

2. Create i18n resource files - Note that you have to create a resource file for your default language. (In this example: './i18n/en.json' and './i18n/de-de.json').

   // en.json
       {
           "title": "Hello World",
           "content": {
               "description": "A little description."
           }
       }
   
   // de-de.json
       {
           "title": "Hallo Welt",
           "content": {
               "description": "Eine kleine Beschreibung."
           }
       }

3. Use lingua in your views - Note that the syntax depends on your template engine. In this example it is: jqtpl and the request comes from a browser which sends 'en' with the HTTP request header.

   <h1>${lingua.title}</h1> <!-- out: <h1>Hello World</h1> -->
   <p>${lingua.content.description}</h1> <!-- out: <p>A little description.</p> -->

4. Let the user select a language - Note that the user's selection is persisted within a cookie. This is an optional step. If you want to let lingua determine the user language from the browser configuration then leave this step out. Anyway, this is a very handy feature for switching the language by a user decision.

   <a href="?language=de-DE">de-DE</a>
   <a href="?language=en-US">en-US</a>

There is an example application at ./example

To run it:

$ cd example
$ node app.js

You can find a deployed version of this app here.

MIT License

Copyright (c) 2011, André König (Google+) (andre.koenig -[at]- gmail [dot] com)