Why is 1 element of Stat empty?

Question

React

Hello, I have the following code

const [item, setItem] = useState({
    id: null, name: "", price: "", weight: ""
  })
  const [cart, setCart] = useState([])


  const addToCart = (id, name, price, weight) => {
    setItem({item, id:id, name:name, price:price, weight:weight})
    setCart(cart => [...cart, item])
  }

When I click on a product, I add it to the cart, and display the cart itself using the map method in the sidebar. There is a problem that when you click on a product in cart 1 of the elements, an item appears with Default values ​​\u200b\u200bthat I set for the InitialState item

Answer 1

For setCart, you need to use useEffect with an item dependency, since adding to the cart is essentially a side effect of setting a new item, in this case

Answer 2

Updating states in react asynchronously happens