Vue JS Internship

// Week 6: one composable, no duplicated cart logic
export function useCart() {
  const store = useCartStore();

  const subtotal = computed(() =>
    store.items.reduce((n, i) => n + i.price * i.qty, 0));

  const shipping = computed(() =>
    subtotal.value > 5000 ? 0: 250);

  async function add(id: string, qty = 1) {
    await store.add(id, qty);          // optimistic in the store
    toast.success("Added to cart");
  }

  return { items: storeToRefs(store).items, subtotal, shipping, add };
}