Singleton

// IMBD MOVIES
// var popular =  newReleases.filter(a=>a.rating===5.0).map(a=>a.id);  get all movies with raiting >= 5.0

Singleton = function()
{
    let instance;
    return {
        getInstance: function ()
        {
            if (!instance)
                instance = Date.now();
            return instance;
        }
    }
}();

// ***************************************************
// Shopping Cart functions

function shoppingCart(){
    this.items = []
}

shoppingCart.prototype.addItemToCart = function(name, price, count){
    for(var i=0; i<this.items.length; i++)
    {
        if(this.items[i].name == name)
        {
            this.items[i].count += count;
            return;
        }
    }

    this.items.push({
        name: name,
        price: price,
        count: count
    })
}
shoppingCart.prototype.setCountForItem = function(name, count){
    if(count > 0)
        for(var i=0; i<this.items.length;i++)
        {
            if(this.items[i].name == name)
            {
                this.items[i].count = count;
                break;
            }
        }
    else {
        this.removeItemFromCart(name);
    }
}

shoppingCart.prototype.removeItemFromCartAll = function(name){
    this.items = this.items.filter(el => {
        return el.name != name
    });
}

shoppingCart.prototype.clearCart = function(){
    this.items = []
}

shoppingCart.prototype.countCart = function(){
    return this.items.map(el => el.count).reduce((acc, el) => acc + el, 0);
}

shoppingCart.prototype.totalCart = function() {
    return this.items.reduce((acc, el) =>{
        acc += el.price * el.count;
        return acc;
    }, 0);
}

shoppingCart.prototype.listCart = function() {
    return this.items.map(el => {
        return {
            ...el,
            total: el.price * el.count
        }
    })
}

var shoppingCart = new shoppingCart();



console.log("Testing Singleton!");
console.log("Creating i1");
console.log("i1 was created at time [Number: " + Singleton.getInstance() + "]");
console.log("Creating i2 at time: " + Date.now());
console.log("i2 was created with time [Number: " + Singleton.getInstance() + "]");
let first =  Singleton.getInstance() === Singleton.getInstance();
console.log("Checking if i1 and i2 are the same instance: " + first);
console.log("Creating i3 in different execution context at time: " + Date.now());
console.log("i3 was created with time [NUmber: " + Singleton.getInstance() + "]");
let second = Singleton.getInstance() === Singleton.getInstance();
let third = Singleton.getInstance() === Singleton.getInstance();
let fourth = Singleton.getInstance() === Singleton.getInstance();
console.log("Checking if i1 and i3 are the same variable: " + second);
console.log("Checking if i2 and i3 are the same variable: " + third);
console.log("Checking if i1 and i2 are the same variable: " + second);