How to aggregate the item products in shopping cart?

Hi team, I am creating a food ordering app. I have created the add food item functionality and once the customer add a food item, the items gets stored in orderLine entity. Now I want a functionality for suppose a customer adds the pizza twice so the total quantity should show as 2 in a single line beside pizza. I have also attached the ss of my domain model and pages and how its currently working for me.   Domain model ss:   Add product in my cart microlfow: Above microfow triggers when click on add to cart button:    
1 answers

Did you take a look at this section of the documentation?

If you retrieve a list, you can count the number of items. You will probably have to add some additional logic for items that are linked to the same menu item.