The Cart that Never Forgets

1import { actor } from "rivetkit";
2
3export const shoppingCart = actor({
4  state: { items: [], history: [] },
5
6  actions: {
7    // Instant recommendations based on hot state
8    recommend: async (c) => {
9      const recent = c.state.history.slice(-5);
10      return await c.ai.recommend(recent);
11    },
12
13    addItem: async (c, { productId, qty }) => {
14      const stock = await c.rpc.inventory.reserve(productId, qty);
15      if (!stock) throw "Out of Stock";
16
17      c.state.items.push({ productId, qty });
18      c.broadcast("cart_updated", c.state);
19    }
20  }
21});