I am trying to create a shopping basket in a JSON array and an array to be stored in the localStorage.

I want to 

1. Check if exists

2. Update the array based on ProductID

3. If it does not exist then add new values to the array

4. Then update the localstorage.

Currently my code does not update e.g. 1 + 1 is 11 instead of 2. What am i doing wrong

SEcondly the array appears to be sub arrays instead of updating it

2.  var Basket = { ProductID: product, Quantity: quantity }; // create shopping basket values
3. 
   
4.                                              //STEP 2 - create an array 
5.                    //  
6.           var  BasketContents = [];  // EMPTY the contents
7.   
8.      
9. 
   
10.             // step 3 - update contents
11.             if (localStorage.BasketContents)              //check contents
12.             {
13.           
14.   
15.          
16.             const update = JSON.parse(localStorage.getItem('BasketContents'));
17.     
18.         
19.             update.forEach(x => {if (x.ProductID == product) 
20.             {
21.             int count = x.Quantity + quantity;
22.             x.Quantity = count;
23.               BasketContents.push(update);
24. 
    
25.              localStorage.removeItem('BasketContents');
26.              localStorage.setItem('BasketContents',  JSON.stringify(BasketContents));
27.        return;
28.             }
29.             else
30.             {
31.              BasketContents.push(Basket);
32.  
33. 
    
34.              localStorage.removeItem('BasketContents');
35.              localStorage.setItem('BasketContents',  JSON.stringify(BasketContents));
36.             return;
37.             }
38.             });