The concept of closures in javascript is important to understand because you might not even know you're doing it. If you write in coffee-script classes or do classical inheritance patterns in vanilla javascript, you are using closures. The following example is a starting point for classical inheritance in javascript. This shows how to hide priva…

carClass.js

function car() {
  
  // Private Variable
  var val = {
    make  : "generic",
    model : "generic",
    color : "generic"
  };
  
  // "new" instance
  return {
    setMake: function(newMake) {
      make = newMake || "generic";
      val.make = make;
    },
    getMake: function() {
      return val.make;
    },
    
    setModel: function(newModel) {
      model = newModel || "generic";
      val.model = model;
    },
    getModel: function() {
      return val.model;
    },
    
    setColor: function(newColor) {
      color = newColor || "generic";
      val.color = color;
    },
    getColor: function() {
      return val.color;
    },
    
    self: function() {
      return val;
    }
  }
}


// Create our instances
var juke1 = car();
var juke2 = car();

// Set make
juke1.setMake("nissan"); 
juke2.setMake("nissan");

// Set model
juke1.setModel("juke");
juke2.setModel("juke");

// Set color
juke1.setColor("red");
juke2.setColor("black");

// Cannot get private variable, cool!
juke1.val  // undefined
juke2.val  // undefined

// Use getter for access to private data
juke1.self() // Object {make: "nissan", model: "juke", color: "red"}
juke2.self() // Object {make: "nissan", model: "juke", color: "black"}