I want to do an onClick counter but I have a problem with the counter iterating correctly. In the app there are 3 "products" and after clicking "Add To Cart" button the state of the object is updated but all of the products are generated separately. I think that is cousing the problem where the counter is different for each of the products or everything will work correctly if I lift the state up, but the console.log is just freshly generated for all of the products. I'm not really sure so I need help with that.
Here is some code in the order from the parent to the last child:
import { useEffect, useState } from "react";
import ProductList from "./ProductList";
const Products = () => {
const [products, setProducts] = useState (null);
useEffect (() => {
fetch('http://localhost:8000/products')
.then(res => {
return res.json();
})
.then(data => {
setProducts(data);
})
}, []);
return (
<div className="ProductList">
{products && <ProductList products={products}/>}
</div>
);
}
export default Products;
import Card from "./Card";
const ProductList = (props) => {
const products = props.products;
return (
<div className="ProductList" >
{products.map((product) => (
<Card product={product} key={product.id} />))}
</div>
);
}
export default ProductList;
import { useState } from "react";
const Card= ({ product }) => {
const [showDescription, setShowDescription] = useState(false);
const [CartCounter, setCartCounter ] = useState(0);
console.log(CartCounter);
return (
<div className="Product-Preview" >
<div className="backdrop" style={{ backgroundImage: `url(${product.image})` }}></div>
<h2>{product.title}</h2>
<div>{product.price}</div>
<button className="ShowDescription" onClick={() => setShowDescription(!showDescription)}>Details</button>
<button className="AddToCart" onClick={() => setCartCounter(CartCounter + 1)}>Add To Cart </button>
{showDescription && <p>{product.description}</p>}
<br />
</div>
);
};
export default Card;
Ok, you want to keep track of an aggregated value. I'll list code in some high level.
const ProductList = () => {
const [count, setCount] = useState(0)
const addOrRemove = n => { setCount(v => v + n) }
return products.map(p => <Card addOrRemove={addOrRemove} />)
}
const Card = ({ addOrRemove }) => {
// optional if you want to track card count
// const [count, setCount] = useState(0)
return (
<>
<button onClick={() => { addOrRemove(1) }>Add</button>
<button onClick={() => { addOrRemove(-1) }>Remove</button>
</>
)
}
Essentially either you track the local count or not, you need to let the parent to decide what is the final count, otherwise there'll be some out of sync issue between the child and parent.