TypeError: Cannot read property 'find' of undefined trying to add extra items to Cart

Question

I am trying to add extra items to the Cart using useContext, but the code keeps crashing with the error of "TypeError: Cannot read property 'find' of undefined". I want to add the items in the Cart and I do not know if this code should work, perhaps i am doing something wrong.

This is the CartProvider code:

import { useState } from "react";
import CartContext from "./CartContext";   

export const CartProvider = ({ children }) => {
    const [list, setList] = useState();  
    const addCart = (varietals) => {
        const isInCart = list.find((x) => x.id === varietals.id);
        if (isInCart) {
            setList(
                list.map((x) =>
                x.id === varietals.id ? { ...isInCart, qty: isInCart.qty + 1 } : x
              )
            );
        }else{                
            setList([...list, { ...varietals, qty: 1 }]);    
        }
    };
    return(
    <>
      <CartContext.Provider value={{list, addCart}}>
          {children}
      </CartContext.Provider>
    </>);
};

Varietals contains all the details of each item.