Code for http://hecticjeff.heroku.com/2010/02/14/an-introduction-to-nodejs/

calc.js

var calculator = {
    add: function (a, b) {
        return a + b
    },
    subtract: function (a, b) {
        return a - b
    },
    multiply: function (a, b) {
        return a * b
    },
    divide: function (a, b) {
        return a / b
    }
}

process.mixin(exports, calculator)

calculator.js

// Assuming that calc.js is in the same dir as this file
var calc = require('./calc')

// Now we can use the calc object to do calculations, joy!
var ten = calc.add(3, 7)
var two = calc.subtract(5, 3)

gistfile2.sh

$ node hello.js
Hello World!

hello.js

var sys = require('sys')

function sayHello (name) {
    return 'Hello ' + name + '!'
}

sys.puts(sayHello('World'))