Items that are filtered out which previously had a quantity selected can still be added to cart

[AndrewLester]

Before adding cartItems to the JSON body that is sent when adding items to your cart, make sure they exist in the refinedItems variable. Here's where they are added to the JSON body:
https://github.com/apc-gmhs/mustang-mug/blob/3e3973ffb904f6e00af51a636d0a364c49e45456/src/routes/_menu.js#L15-L23
This method should take in another parameter (availableItems or similar) with the items that are currently displayed to the user (refinedItems in the Menu component). The Menu component must also export its refinedItems property so that it may be accessed in the index.svelte (menu) route.

[AndrewLester]

The intended behavior of this must be discussed further before implementing a solution.

Also, filtering out an item and bringing it back removes a previously selected quantity.