Encountered two children with the same key...ecommerce website - reactjs

Question

why is it that there are two children with the same key
Im using React and Im trying to make ecommerce website
I dont understand the error of double keys
import React, {useEffect} from 'react'
import { Link, useParams, useNavigate, useLocation, useSearchParams } from 'react-router-dom'
import { useDispatch, useSelector } from 'react-redux'
import { Row, Col, ListGroup, Image, Form, Button, Card} from 'react-bootstrap'
import Message from '../components/Message'
import { addToCart } from '../actions/cartActions'
export default function CartScreen() {
const { id} = useParams()
const { search } = useLocation();
const [searchParams] = useSearchParams();
const dispatch = useDispatch();
const productID = id;
const qty = search ? Number(search.split("=")[1]) : 1;
const cart = useSelector(state => state.cart)
const { cartItems} = cart
console.log('cartItems:', cartItems)
useEffect(() => {
if(productID) {
dispatch(addToCart(productID, qty))
}
}, [dispatch, productID, qty])
return (
<Row>
<Col md={8}>
<h1>Shopping Cart</h1>
{cartItems.length === 0 ? (
<Message variant='info'>
Your cart is empty <Link to='/'>Go Back</Link>
</Message>
) : (
<ListGroup varient='flush'>
{cartItems.map(item => (
<ListGroup.Item key= { item.product }>
<Row>
<Col md={2}>
<Image src={item.image} alt={item.name} fluid rounded/>
</Col>
<Col md={3}>
<Link to={`/product/${item.product}`}>{item.name}</Link>
</Col>
<Col md={2}>
${item.price}
</Col>
</Row>
</ListGroup.Item>
))}
</ListGroup>
)}
</Col>
<Col md={4}>
</Col>
</Row>
)
}
Im trying to load up the cart images in the CartScreen
and its telling me that there are two children with same key

Answer 1

In React while using the following
<ListGroup.Item key= { uniqueID }>
Every key value has to be unique such that it can identify each item in the list uniquely.
More help from this thread.

Answer 2

key is not unique for the elements rendered, React found two elements with same key. Could you please try modifying the map JSX inside map.
<ListGroup varient='flush'>
{cartItems.map((item, index) => (
<ListGroup.Item key= { `${item.product}i${index}` }>
<Row>
<Col md={2}>
<Image src={item.image} alt={item.name} fluid rounded/>
</Col>
<Col md={3}>
<Link to={`/product/${item.product}`}>{item.name}</Link>
</Col>
<Col md={2}>
${item.price}
</Col>
</Row>
</ListGroup.Item>
))}
</ListGroup>