See if cart is empty

lib/bigcommerce/api/cart.ts

@@ -23,6 +23,12 @@ export type Cart = {
   base_amount: number
   discount_amount: number
   cart_amount: number
+  line_items: {
+    custom_items: any[]
+    digital_items: any[]
+    gift_certificates: any[]
+    psysical_items: any[]
+  }
   // TODO: add missing fields
 }
 

lib/bigcommerce/cart/index.tsx

@@ -18,8 +18,14 @@ export const CartProvider: FC = ({ children }) => {
 export function useCart() {
   const cart = useCommerceCart<Cart>()
 
-  // TODO: Do something to make this prop work
-  cart.isEmpty = true
+  Object.defineProperty(cart, 'isEmpty', {
+    get() {
+      return Object.values(cart.data?.line_items ?? {}).every(
+        (items) => !items.length
+      )
+    },
+    set: (x) => x,
+  })
 
   return cart
 }