Book Store using Factory Function vs Constructor Function

gistfile1.txt

// Factory Function 
function CreateBookStore(inventory) {
    return {
        inventory, 
        getInventoryValue() {
            // if arrow function is used here, this will return `undefined`, 
            // hence using short-hand/object literal for function 
            // this is similar to `getInventoryValue: function () { ......... }`
            return this.inventory.reduce((total, book) => total + book.price, 0);
        },
        getBookDetails(name) {
            // Find is better to use here than filter 
            // because we need only ONE book from the inventory
            return this.inventory.find(book => book.name===name);
        },
        addBookDetails({name, price}){
            return this.inventory.push({name, price})
        }
    }
}

const bookStoreInventory =  [
    {
        name: 'Jay Shetty',
        price: 300
    }, 
    {
        name: 'Harry Potter',
        price: 450
    }
]

var myBookStore = CreateBookStore(bookStoreInventory)

myBookStore.addBookDetails({ name: 'Lord of the rings', price: 500})
myBookStore.getInventoryValue() // should return 1250
myBookStore.getBookDetails('Lord of the rings') // {name: 'Lord of the rings', price: 500}

// -------------------------------------------------------------------------------- //

// Constructor Function 

function CreateBookStore(inventory) {
    this.inventory = inventory;
}

CreateBookStore.prototype.getInventoryValue = function() {
    return this.inventory.reduce((total, book) => total + book.price, 0);
};

CreateBookStore.prototype.getBookDetails = function(name) {
    return this.inventory.find(book => book.name===name);
};

CreateBookStore.prototype.addBookDetails = function({name, price}){
    return this.inventory.push({name, price})
}

const bookStoreInventory =  [
    {
        name: 'Jay Shetty',
        price: 300
    }, 
    {
        name: 'Harry Potter',
        price: 450
    }
]

var myBookStore = new CreateBookStore(bookStoreInventory)

myBookStore.addBookDetails({ name: 'Lord of the rings', price: 500})
myBookStore.getInventoryValue() // should return 1250
myBookStore.getBookDetails('Lord of the rings') // {name: 'Lord of the rings', price: 500}