I need to make a list of objects based on combined data from 2 arrays, one comes from a localStorage and the second one from Django backend. First of all objects from localStorage are displayed by showCart()
function
export const showCart = () => { if (typeof window !== undefined) { if (localStorage.getItem("cart")) { return JSON.parse(localStorage.getItem("cart")); }; }; };
it returns data in this format: FE: { id: 1, amount: 7, size: "L", product: 1 }
. product
is the Foreign Key needed to match data from other array.
The second array comes form a backend and it is feched by getAllProducts()
function
export const getAllProducts = () => { return fetch(`${url}/products/`, {method: "GET"}) .then((response) => { return response.json(); }) .catch((error) => console.log(error)) };
It returns data in this format: FE { name: "Red", id: 3, price: 33, image:"some-url"}
ββ
Now I need to create another list of objects by merging then by product
of an object in first array with id
of an object from the second one. The objects in the third array need to contain amount
and size
from first array as well as name
, price
and image
from the second one. In the end I want to store it in useState()
.
This is what I came up with, I guess my code stops working arter first for loop:
const [cart, setCart] = useState([]); const CheckAnonymousCart = () => { getAllProducts() .then((data) => { const localCart = showCart(); var products = []; for (let i = 0; i < localCart.lenght; i++) { for (let y = 0; y < data.lenght; y++) { if (localCart[i].product === data[y].id) { console.log(localCart[i].product, data[y].id) const item = { name: data[y].name, price: data[y].price, image: data[y].image, amount: localCart[i].amount, size: localCart[i].size, } products.push(item) break; } } } setCart(products); }) .catch((error) => console.log(error)) };
ββAny thoughts?
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Answer
In addition to Jacob’s comment, you probably want to avoid FETCH
‘ing all products from the DB, because it requires more DB resources, most of the info is not required, and it makes the for-loop take longer to JOIN
both lists.
Ideally, you would use a parameterized query like so:
return fetch(`${url}/products/?id=1&id=2&id=3`, {method: "GET"})
Where ?id=1&id=2&id=3
are a subset of the product IDs that you’re retrieving.
Note: You will also want to sanitize/validate the product IDs in localStorage
, because the data can be modified by the end-user, which is a potential attack vector by malicious users.