decorator_classic_oop_pattern.js

/**
 * ConcreteComponent
 * (класс для последующего декорирования)
 */
class Coffee {
	getCost(defCost:number = 1):number {
		return defCost;
	}
}

abstract class CoffeeItem {
	protected cost:number;

	constructor(protected coffee:Coffee) {
	}

	public getCost():number {
		return this.coffee.getCost() + this.cost;
	}
}

/**
 * Decorator A
 */
class Milk extends CoffeeItem {
	protected cost = 0.5;
}

/**
 * Decorator B
 */
class Whip extends CoffeeItem {
	protected cost = 0.7;
}

/**
 * Decorator C
 */
class Sprinkles extends CoffeeItem {
	protected cost = 0.2;
}


var coffee =
	new Milk(
		new Whip(
			new Sprinkles(
				new Coffee()
			)
		)
	);
	
console.log(coffee.getCost());