使用数组和函数在 JavaScript 中构建初学者友好的购物车的分步指南

const itemnames = ["laptop", "phone"];const itemprices = [1000, 500];const itemquantities = [1, 2];const iteminstock = [true, true];

const shoppingcart = () => {  const cart = []; // the cart is a private array  // add an item to the cart  const additemtocart = (itemindex) => {    if (iteminstock[itemindex]) {      cart.push(itemindex);      console.log(`${itemnames[itemindex]} added to the cart`);    } else {      console.log(`${itemnames[itemindex]} is out of stock`);    }  };  // remove an item from the cart  const removeitemfromcart = (itemindex) => {    const index = cart.indexof(itemindex);    if (index > -1) {      cart.splice(index, 1);    }  };  // get the names of items in the cart  const getcartitems = () => {    return cart.map(itemindex => itemnames[itemindex]);  };  // calculate the total price of items in the cart  const calculatetotal = () => {    return cart.reduce((total, itemindex) => {      return total + itemprices[itemindex] * itemquantities[itemindex];    }, 0);  };  return {    additemtocart,    removeitemfromcart,    getcartitems,    calculatetotal  };};

const mycart = shoppingcart();// add a laptop (item 0)mycart.additemtocart(0);// add a phone (item 1)mycart.additemtocart(1);// view cart contentsconsole.log(mycart.getcartitems()); // output: ['laptop', 'phone']// calculate the total priceconsole.log(mycart.calculatetotal()); // output: 2000

mycart.removeitemfromcart(1); // remove the phone// view the updated cartconsole.log(mycart.getcartitems()); // output: ['laptop']// recalculate the total priceconsole.log(mycart.calculatetotal()); // output: 1000

const itemNames = ["Laptop", "Phone"];const itemPrices = [1000, 500];const itemQuantities = [1, 2];const itemInStock = [true, true];const ShoppingCart = () => {  const cart = [];  const addItemToCart = (itemIndex) => {    if (itemInStock[itemIndex]) {      cart.push(itemIndex);      console.log(`${itemNames[itemIndex]} added to the cart`);    } else {      console.log(`${itemNames[itemIndex]} is out of stock`);    }  };  const removeItemFromCart = (itemIndex) => {    const index = cart.indexOf(itemIndex);    if (index > -1) {      cart.splice(index, 1);    }  };  const getCartItems = () => {    return cart.map(itemIndex => itemNames[itemIndex]);  };  const calculateTotal = () => {    return cart.reduce((total, itemIndex) => {      return total + itemPrices[itemIndex] * itemQuantities[itemIndex];    }, 0);  };  return {    addItemToCart,    removeItemFromCart,    getCartItems,    calculateTotal  };};const myCart = ShoppingCart();myCart.addItemToCart(0);myCart.addItemToCart(1);console.log(myCart.getCartItems());console.log(myCart.calculateTotal());myCart.removeItemFromCart(1);console.log(myCart.getCartItems());console.log(myCart.calculateTotal());