Advanced Functions:
===================
Arrow Functions:
================
-> introduced in ES6 (ECMAScript 2015)
-> Arrow function is the compact way to define the function.
-> Arrow function possible to define without "function" keyword.

const orders = [
    {id : 1,status :"pending"},
    {id : 2,status : "delivered"},
    {id : 3,status : "shipped"},
    {id : 4,status : "delivered"}
    ];
    
// without arrow functions
const deliveredOrders = orders.filter(function(order){
    return order.status === "delivered"; // anonymous function ==> Nameless functions
})
console.log(deliveredOrders);

// with arrow function

console.log("The Products which are already delivered:");

const delivered = orders.filter(order => order.status === "delivered");

console.log(delivered);
==================================================
Function Invocations:
=====================
==> The function can call in different ways:
	1) Direct Call
	2) as an Object Properties
	3) New Keyword
	4) using call(), apply() and bind()
	5) Automatic way

// Online shopping cart

function calculateTotal(cartItems){
    let total = 0
    cartItems.forEach(item => {
        total += item.price * item.quantity;
    });
    return total;
}
let cart = [
    {name:"Laptop",price:50000,quantity:1},
    {name:"Moouse",price:1100,quantity:2},
    {name:"Keyboard",price:2500,quantity:1}
    ];

// Direct Call to the function ==> Traditional way of calling the function
const totalPriceOfTheCart = calculateTotal(cart);
console.log("The Total Cost of Products from the cart = ",totalPriceOfTheCart);
// Function call as a object property
const shoppingCart = {
    cartItems : cart,
    calculateTotal(){
        return calculateTotal(this.cartItems);
    }
};
console.log(shoppingCart.calculateTotal());

// using call()
const otherCart = [
    {name:"mobilePhone",price:25000,quantity:1},
    {name:"charger",price:1500,quantity:1}
    ];
    
const totalOtherCart = calculateTotal.call(null,otherCart);
console.log(totalOtherCart);
==========================================
apply():
=======
function calculateAge(currentYear){
    return currentYear - this.birthYear;
}

let person = {
    name : "Karthik",
    birthYear:1993
};

let anotherPerson = {
    name : "Kishore",
    birthYear : 1996
};

let kathikAge = calculateAge.apply(person,[2025]);
console.log("The Age of Karthik = ",kathikAge);

let kishoreAge = calculateAge.apply(anotherPerson,[2025]);
console.log("The Age of Kishore = ",kishoreAge)
=====================================================
bind():
======

let student1 = {
    name : "Rajesh",
    grade : "A",
    selfIntro:function(){
        console.log(this.name+" My Grade is = "+this.grade);
    }
};
let student2 = {
    name : "Keerthana",
    grade : "B",
}

let result = student1.selfIntro.bind(student2);

result()