BlueprintJS

var User = blueprint({
    name: "",
    lastName: "",
    fullName: function () {
        "use strict";
        // Never use this.name, always use the "get" and "set" methods
        return this.get("name") + " " + this.get("lastName");
    }
});

var someObjectIHaveInMyProject = {name: "Robert", lastName: "Baratheon"};

var user = new User(someObjectIHaveInMyProject);

// Now you get the "fullName" method for free. Bargain!
console.log(user.get("fullName")); // Robert Baratheon

user.set("lastName", "Downey Jr.");

console.log(user.get("fullName")); // Robert Downey Jr.

var userPlainObject = blueprint.toPlainObject(user);

// Note that the fullName method is now a property with a value that is the
// result of that method
console.log(user.fullName); // Robert Downey Jr.

var listOfObjects = [
    {name:"John", lastName: "Blue"},
    {name:"Mary", lastName: "Red"},
    {name:"Richard", lastName: "Green"},
    {name:"Michael", lastName: "Gray"},
    {name:"Agatha", lastName: "Orange"}
];

// blueprint.cast(Blueprint, object_or_list_of_objects)
var listOfUsers = blueprint.cast(User, listOfObjects);

console.log(listOfUsers[1].get("fullName")); // Mary Red

var Car = blueprint({
    init: function () {
        this.set("model", "BMW"); // It will replace the default model
    },
    model: "Mercedes Benz"
});

// The object is created and the "init()" method is called
var car = new Car();

console.log(car.get("model")); // BMW

// Just require the package and you are set
var blueprint = require("blueprint");

var Car = blueprint({
    // Using closure and IIFE to create the isExpensive method
    isExpensive: (function (){
        "use strict";
        // "Static" list of expensive brands
        var expensiveBrands = {
            bmw: true,
            mercedez: true
        };
        // The function that will be executed when the
        // isExpensive method is called
        return function () {
            if (expensiveBrands[this.get("brand")]) {
                return true;
            }
            return false;
        };
    }())
});

var car = new Car({brand:"bmw"});

console.log("Is the car expensive? " + car.get("isExpensive"));
// outputs: Is the car expensive? true