购物车类 JavaScript

Question

i want to make a shopping cart with JavaScript, i want make a Class that called 'Cart' that have a function like this

addProduct (productcode, quantity)

• this is a function to add product and will increment the quantity if we add the same product

deleteProduct (productcode)

• this is a function to delete the product

showcart()

• this is a function that will show the product and the quantity in the cart

so far i have done this

  class Cart{
    constructor(productcode, quantity){
        this.productcode = productcode;
        this.quantity = quantity;
        

    }
    addProduct (productcode, quantity){
        
        
        
    }
    deleteProduct (productcode){

    }
    showcart(){

    }
}
 

have no idea what to do next

Answer 1

this is how I would go about it , you can test the snippet

 class CartItem{ constructor(title,price, quantity){ this.title = title; this.price = price; this.quantity = quantity; this.updateQuantity.bind(this) } updateQuantity( quantity){ this.quantity +=quantity } } class Cart{ constructor(){ this.cartItems = []; this.addItem.bind(this) this.removeItem.bind(this) this.showcart.bind(this) this.checkIfItemExists.bind(this) } addItem(cartItem){ //if item s already added to cart increment its quantity const alreadyInCart=mycart.checkIfItemExists(cartItem.title) if(alreadyInCart) return cartItem.updateQuantity(cartItem.quantity) //else just add the tem this.cartItems.push(cartItem) } checkIfItemExists(title){ return this.cartItems.filter(item=> item.title == title)[0] != undefined } removeItem (title){ this.cartItems= [...this.cartItems].filter(item=>item.title !=title ) } showcart(){ console.log(this.cartItems) } } const item1 = new CartItem('item1',20,1) const item2= new CartItem('item2',20,1) const mycart = new Cart() mycart.addItem(item1) mycart.addItem(item1) mycart.addItem(item2) mycart.showcart()