How do I make a shopping cart to be able to interact with a server using node.js?

Question

I am confused on how do I make a shopping cart to be able to interact with a server in the back end using node.js. This is what I got so far using JS. I have it as local storage, but I do not know how to make it to the actual server using node.js.

let productsInCart = JSON.parse(localStorage.getItem('ShoppingCart'));
if(!productsInCart){
  productsInCart = [];
}
const parentElement =  document.querySelector('#buyItems');
const cartSumPrice = document.querySelector ('#sum-prices');
const products = document.querySelectorAll ('.product-under');


const countTheSumPrice = function(){
  let sumPrice = 0;
  productsInCart.forEach(product => {
    sumPrice += product.price;
  });
  return sumPrice;
}

const updateShoppingCartHTML = function(){
  localStorage.setItem('ShoppingCart',JSON.stringify(productsInCart));
      if (productsInCart.length > 0){
         let result = productsInCart.map(product => {
            return 'fill in the blank'
            
        
          });
          parentElement.innerHTML = result.join('')
          document.querySelector('.checkout').classList.remove('hidden');
          cartSumPrice.innerHTML = "$" + countTheSumPrice();

      }
      else{
        document.querySelector('.checkout').classList.add('hidden');
        parentElement.innerHTML = '<h4 class="empty">Your shopping cart is empty</h4>';
        cartSumPrice.innerHTML = "";
      }
}

function updateProdcutsInCart(product){
  for(let i=0; i < productsInCart.length; i++){
    if(productsInCart[i].id == product.id){
      productsInCart[i].count += 1;
      productsInCart[i].price = productsInCart[i].basePrice * productsInCart[i].count;
      return;
    }
  }
  productsInCart.push(product);
}





products.forEach(product => {
  product.addEventListener('click', (e) =>{
    if (e.target.classList.contains('addToCart')){
         const productID = e.target.dataset.prodcutID;
         const productName = product.querySelector('.productName').innerHTML;
         const productPrice = product.querySelector('.priceValue').innerHTML;
         const productImage = product.querySelector ('img').src;
         let productToCart = {
             name: productName,
             image: productImage,
             id: prodcutID,
             count: 1,
             price: +productPrice,
             basePrice : +productPrice
         }
        updateProdcutsInCart(productToCart);
        updateShoppingCartHTML(); 

    }
  });
});

parentElement.addEventListener('click', (e) =>{
  const isPlusButton = e.target.classList.contains('button-plus');
  const isMinusButton = e.target.classList.contains('button-minus');
  if (isPlusButton || isMinusButton){
    for(let i=0; i < productsInCart.length; i++){
      if (productsInCart[i].id === e.target.dataset.id){
        if(isPlusButton){
            productsInCart[i].count += 1;
        }
        else if(isMinusButton){
          productsInCart[i].count -= 1;
        }
        productsInCart[i].price = productsInCart[i].basePrice * productsInCart[i].count;
      }
      if(productsInCart[i].count <=0){
        productsInCart.splice(i,1);
      }
    }
    updateShoppingCartHTML();
  }
});

updateShoppingCartHTML()

I tried finding a solution online but got lost in the process.

Answer 1

You need a back-end framework for nodeJS like expressJS. Although it can be done in pure node, its better to use express as it makes your life a whole lot easier. You can use http methods to recieve or send data from/to your server.