Sup guys if you have any issues with adding products to local storage here is the code or you wanna Margaret to next.js 13 here is the repo

[OsamaHIma]

`"use client";
import { createContext, useContext, useState } from "react";
import { toast } from "react-hot-toast";

const Context = createContext();

export const StateContext = ({ children }) => {
// Get all data from local storage
const cartItemsFromStorage = JSON.parse(window.localStorage.getItem("cartItems"));
const totalPriceFromStorage = JSON.parse(window.localStorage.getItem("totalPrice"));
const totalQuantitiesFromStorage = JSON.parse(
window.localStorage.getItem("totalQuantities")
);
const qtyFromStorage = JSON.parse(window.localStorage.getItem("qty"));

const [showCart, setShowCart] = useState(false);

// set the data from local storage as the default state and if it doesn't exist add default state
const [cartItems, setCartItems] = useState(cartItemsFromStorage || []);
const [totalPrice, setTotalPrice] = useState(totalPriceFromStorage || 0);
const [totalQuantities, setTotalQuantities] = useState(
totalQuantitiesFromStorage || 0
);
const [qty, setQty] = useState(qtyFromStorage || 1);
// set local storage data
window.localStorage.setItem("totalQuantities", totalQuantities);
window.localStorage.setItem("totalPrice", totalPrice);
window.localStorage.setItem("qty", qty);

let foundProduct;
let index;

const onAdd = (product, quantity) => {
const checkProductInCart = cartItems.find(
(item) => item._id === product._id
);

setTotalPrice(
  (prevTotalPrice) => prevTotalPrice + product.price * quantity
);

setTotalQuantities((prevTotalQuantities) => prevTotalQuantities + quantity);

if (checkProductInCart) {
  const updatedCartItems = cartItems.map((cartProduct) => {
    if (cartProduct._id === product._id)
      return {
        ...cartProduct,
        quantity: cartProduct.quantity + quantity,
      };
  });

  setCartItems(updatedCartItems);
  window.localStorage.setItem("cartItems", JSON.stringify(updatedCartItems));
} else {
  product.quantity = quantity;

  setCartItems([...cartItems, { ...product }]);
  window.localStorage.setItem(
    "cartItems",
    JSON.stringify([...cartItems, { ...product }])
  );
}

toast.success(`${qty} ${product.name} added to the cart.`);

};

const onRemove = (product) => {
foundProduct = cartItems.find((item) => item._id === product._id);
const newCartItems = cartItems.filter((item) => item._id !== product._id);

setTotalPrice(
  (prevTotalPrice) =>
    prevTotalPrice - foundProduct.price * foundProduct.quantity
);

setTotalQuantities(
  (prevTotalQuantities) => prevTotalQuantities - foundProduct.quantity
);

setCartItems(newCartItems);
window.localStorage.setItem("cartItems", JSON.stringify(newCartItems));

};

const toggleCartItemQuantity = (id, value) => {
foundProduct = cartItems.find((item) => item._id === id);
index = cartItems.findIndex((product) => product._id === id);
const newCartItems = cartItems.filter((item) => item._id !== id);

if (value === "inc") {
  setCartItems([
    ...newCartItems,
    { ...foundProduct, quantity: foundProduct.quantity + 1 },
  ]);
  window.localStorage.setItem(
    "cartItems",
    JSON.stringify([
      ...newCartItems,
      { ...foundProduct, quantity: foundProduct.quantity + 1 },
    ])
  );

  setTotalPrice((prevTotalPrice) => prevTotalPrice + foundProduct.price);

  setTotalQuantities((prevTotalQuantities) => prevTotalQuantities + 1);

} else if (value === "dec") {
  if (foundProduct.quantity > 1) {
    setCartItems([
      ...newCartItems,
      { ...foundProduct, quantity: foundProduct.quantity - 1 },
    ]);
    window.localStorage.setItem(
      "cartItems",
      JSON.stringify([
        ...newCartItems,
        { ...foundProduct, quantity: foundProduct.quantity - 1 },
      ])
    );
    setTotalPrice((prevTotalPrice) => prevTotalPrice - foundProduct.price);
    setTotalQuantities((prevTotalQuantities) => prevTotalQuantities - 1);
    window.localStorage.setItem("totalQuantities", totalQuantities);
  }
}

};

const incQty = () => {
setQty((prevQty) => prevQty + 1);
};

const decQty = () => {
setQty((prevQty) => {
if (prevQty - 1 < 1) return 1;

  return prevQty - 1;
});

};

return (
<Context.Provider
value={{
showCart,
setShowCart,
incQty,
decQty,
onAdd,
toggleCartItemQuantity,
onRemove,
setCartItems,
setTotalPrice,
setTotalQuantities,
setQty
}}
>
{children}
</Context.Provider>
);
};

export const useStateContext = () => useContext(Context);
`

so we going to get all products from the local storage and not from the state context anymore for instance if you want to get the cartItms array in Cart.JSX you have to write following code const cartItems = JSON.parse(window.localStorage.getItem("cartItems"));
and so on for total price and total quantities const totalPrice = JSON.parse(window.localStorage.getItem("totalPrice")); const totalQuantities = JSON.parse(window.localStorage.getItem("totalQuantities"));

And if you have any issues here is my repo
it's next.js 13 but it's not entirely done there are some bugs in the building process.