Decorator Pattern

The Decorator Pattern is

(also known as Wrapper, an alternative naming shared with the Adapter pattern) is a design pattern that allows behavior to be added to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class.

Decorator Pattern ensures

Modifying object functionality

var Product = function (name, brand, price) {
    this.name = name;
    this.brand = brand;
    this.price = price;
}

Base Object

var ReturnedProduct = function (product, deliveryCost) {
    this.product = product;
    this.name = product.name;
    this.brand = product.brand;
    this.price = product.price;
    this.deliveryCost = deliveryCost;
}

Decorator Object

Decorator Object Wrapping

Instance-creating with Base Class

var product = new Product ('shoes', 'adidas', 55, 5);

Instance-creating with Decorator Class

var decoratedProduct = new ReturnedProduct (product, 22);

A decorator example

var ReturnedProduct = function (product, deliveryCost) {
    this.product = product;
    this.name = product.name;
    this.brand = product.brand;
    this.price = product.price;
    this.deliveryCost = deliveryCost;
}

var product = new Product ('shoes', 'adidas', 55, 5);

var decoratedProduct = new ReturnedProduct (product, 22);

Name of decorated product is

this.name = 'Shoes'

Brand of decorated product is

this.brand = 'Adidas'

Our new decorated object is initialized with

this.product = product

Price of decorated product is

this.price = 55

Delivery Cost of decorated product is

this.deliveryCost = 22

Demo

thanks

@hwclass