Javascript Call and Apply - ES6

js-call-apply.es6.js

function notifyClient(message) {
  alert(message);
}

function sendMail(customer, total) {  
  notifyClient.call(this, `TODO: Send mail, (${String(customer.id)}, ${String(total)})`);
}

function getDeals() {  
	var product = arguments[0];
  var minPrice = arguments[1];
  
  product.price = Math.round(product.price * 0.9, 2);
  
  if(product.price < minPrice) {
  	product.price = minPrice;
  }
}

class ShopCart{
  constructor() {
  	this.items = [];
    this.customer = { id: 1 };
  }

  total() {
    var total = 0;
    var item;

    for(var i=0, c=this.items.length; i<c; i++){
      item = this.items[i];
      total += item.price * item.quantity; 
    }

    return total;
  }

  addItem(product) {
    this.getDealsByProduct(product);
    this.items.push(product);
    notifyClient.call(this, 'Item added ' + product.name);
  }

  getDealsByProduct(product) {
    getDeals.apply(this, [product, product.price * 0.6]);
  }

  placeOrder() {
    sendMail.apply(this, [this.customer, this.total()]);
  }
};

var shopCart = new ShopCart();

shopCart.addItem({
  id: 1,
  name: 'Xbox Game',
  price: 179.00,
  quantity: 1
});

shopCart.placeOrder();