/*jslint node: true */
"use strict";

var express   = require('express'),
    router    = require('./libs/routers/router.js'),
    configure = require('./libs/config.js'),
    app       = express();

// Configuration des routes
configure(app);

// Initialisation des routes
router(app);

app.listen(3000, function () {
    console.info('Server connected');
});

module.exports = app;
"use strict"

const express   = require('express')
const router    = require('./libs/routers/router.js')
const configure = require('./libs/config.js')
const app       = express()

// Configuration des routes
configure(app)

// Initialisation des routes
router(app)

app.listen(3000, () => {
    console.info('Server connected')
})

module.exports = app

Update app.js to ES6