Front-End Web Development: The Big Nerd Ranch Guide

For the More Curious: Private Module Data

Inside a module, your constructors and prototype methods have access to any variables declared inside the IIFE. As an alternative to adding properties to the prototype, this is a way to share data between instances but make it hidden from any code outside the module. It looks like this:

(function (window) { 'use strict'; var App = window.App || {}; var launchCount = 0; function Spaceship() { // Initialization code goes here } Spaceship.prototype.blastoff = function () { // Closure scope allows access to the launchCount variable launchCount++; console.log('Spaceship launched!') } Spaceship.prototype.reportLaunchCount = function () { console.log('Total number of launches: ' + launchCount); } App.Spaceship ...