You are a startup founder building a new online marketplace that connects small, independent farmers with consumers who are passionate about buying local and supporting sustainable agriculture. In this marketplace, farmers will be able to create profiles and list their products, and consumers will be able to browse and purchase products directly from the farmers.

1. You can run any of the files with the command node PATH_TO_FILE.
2. To run the tests, do the following in the root folder of this project:

npm install
npm test

1. In Product.js, create a class called Product using the following class diagram above. Product should have the following properties and methods:
   • Properties
     • name, price, and description are set by the constructor method.
     • inStock is set to true when the instance of the class is created.
   • Methods
     • display() returns a string in the following format "Name: <NAME>, Price: $<PRICE>, Description: <DESCRIPTION>".
2. Export the class using module.exports.
3. Import the class into index.js with the name Product.
4. Save and run npm test. The first 3 tests should now pass.

const carrots = new Product("Carrots", 4, "Bushel of carrots that have been freshly harvested for you");

carrots.inStock; // true
carrots.display(); // "Name: Carrots, Price: $4, Description: Bushel of carrots that have been freshly harvested for you"

As your online marketplace grows, you realize that users need a way to save products they want to buy for later. To address this, you decide to build a Cart object that will allow users to add and remove products.

1. In Cart.js, create a class called Cart using the class diagram above. Cart should have the following properties and methods:
   • Properties
     • products: An array that will store instances of Product that have been added to the cart. Starts as an empty array.
     • total: A number representing the total cost of all products in the cart. Starts with a value of 0.
   • Methods
     • addProduct: A method that adds a Product instance to the end of the products array and updates the total property accordingly.
     • removeProduct(i): A method that removes a Product instance from the products array at a specified index i and updates the total property accordingly.
2. Export the class using module.exports.
3. Import the class into index.js with the name Cart.
4. Save and run npm test. 6 tests should now pass.

const strawberries = new Product("Strawberries", 5, "The freshest fresas on the market");
const carrots = new Product("Carrots", 2, "Perfect for an afternoon snack");
const mangos = new Product("Mangos", 3, "The tastiest fruit you can buy");

const myCart = new Cart();
myCart.addProduct(strawberries);
myCart.addProduct(mangos);
myCart.products; // [Product { ... }, Product { ... }]
myCart.total; // 8

myCart.removeProduct(1);
myCart.products; // [Product { ... }]
myCart.total; // 5

With the Product and Cart classes in place, you've got the basic building blocks for a fully functional online marketplace. However, you're missing a key piece of the puzzle: customers!

1. Every Customer can has a Cart that can contain many Product items. In Customer.js, create a class called Customer using the class diagram above. Customer should have the following properties and methods:

   • Properties
     • name, email, and shippingAddress are set by the constructor method.
     • orderHistory contains an array of past Cart items. It initializes as an empty array.
   • Methods
     • addToOrderHistory(cart): adds a Cart instance to the end of the orderHistory array.

2. In Customer.js, export the Customer class using module.exports.

3. Import the class into index.js with the name Customer.

4. Save and run npm test. 9 tests should now pass.

const melanie = new Customer("Melanie", "[email protected]", "22 Main St");
const strawberries = new Product("Strawberries", 5, "The freshest fresas on the market");
const carrots = new Product("Carrots", 2, "Perfect for an afternoon snack");
const mangos = new Product("Mangos", 3, "The tastiest fruit you can buy");

const myFirstOrder = new Cart();
myFirstOrder.addProduct(mangos);
myFirstOrder.addProduct(carrots);

const mySecondOrder = new Cart();
mySecondOrder.addProduct(strawberries);

melanie.addToOrderHistory(myFirstOrder);
melanie.addToOrderHistory(mySecondOrder);

melanie.orderHistory; 
/*
[ 
    Cart { products: [ [Product], [Product] ], total: 5 },
    Cart { products: [ [Product] ], total: 5 },
]
*/

With the Product, Cart, and Customer classes in place, your online marketplace is starting to take shape. However, we need to verify the customers are who they say they are. We will do this with an Auth class.

1. In Auth.js, create a class called Auth using the class diagram above. Create a new class Auth with the following properties and methods:
   • Properties
     • customers: an array that will store instances of the Customer class representing all registered customers. Initializes as an empty array.
   • Methods
     • register(name, email, shippingAddress): a method that creates a new Customer instance with the provided information and adds it to the customers array
     • login(email): a method that takes an email as an argument and returns the corresponding Customer instance from the customers array.
2. Export the Auth class using module.exports.
3. Import the class into index.js with the name Auth.
4. Save and run npm test. All tests should now pass.

let auth = new Auth();
auth.register("Kaiya", "[email protected]", '121 Main St');
auth.register("Nina", "[email protected]", '22 Broadway St');

console.log(auth.login("[email protected]"));
/*
{ name: 'Kaiya', email: '[email protected]', shippingAddress: '121 Main St' }
}
*/

console.log(auth.login("[email protected]")); // null

Business is booming! Here are few extensions you can add to your existing code:

1. Add a getTotal method to the Cart class that returns the total price of all items in the cart.
2. Add a clear method to the Cart class that clears all products from the cart and sets total back to 0.
3. Add a rewardPoints property to the Product class constructor that denotes how many reward points each item gets. In the Customer class:
   • Create a rewardPoints property that initializes with a value of zero.
   • Create a getRewardPoints method that goes through the orderHistory and updates rewardPoints with the number of rewardsPoints that the customer has earned based on their order history.
4. Add a removeItemByName method to the Cart class that removes a specified item from the cart. This method should take in a Product name as an argument and remove that item from the cart.
5. quantity: We have more than 1 of many items in stock. Do the following:
   • Update Product constructor to accept a property of quantity.
   • Update the Cart method addProduct(product, quantity) to accept a quantity argument. The method should:
     • Check that the product has enough quantity to complete the command. If the amount requested is greater than the amount available return I'm sorry there are only QUANTITY of this product left.
     • If there is enough of the quantity, add the item to the cart, increase the total, and then decrease the products quantity.
     • Check if product now has a quantity of 0. If it does, set inStock to false.
     • Return the updated Product.