> ## Documentation Index
> Fetch the complete documentation index at: https://docs.reorderjs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Cart

> How to handle subscription state in the cart — displaying cadence, enforcing purchase mode, and blocking mixed carts.

Once a customer adds a subscription item to their cart, the cart needs to reflect the subscription context clearly and enforce the constraints required by the checkout flow.

## Purchase mode

The cart's purchase mode is derived from line item metadata. Three modes are possible:

| Mode           | Condition                                          |
| -------------- | -------------------------------------------------- |
| `one-time`     | No subscription line items in the cart             |
| `subscription` | All line items are subscription items              |
| `mixed`        | Cart contains both subscription and one-time items |

Use a helper like `getCartPurchaseMode(cart)` to derive the current mode from line item metadata and drive your cart UI accordingly.

## Displaying subscription items

For each subscription line item, show the billing cadence alongside the product. The cadence is stored in the line item's metadata fields `frequency_interval` and `frequency_value`:

```typescript theme={null}
const isSubscription = item.metadata?.is_subscription === true;
const interval = item.metadata?.frequency_interval; // e.g. "month"
const value = item.metadata?.frequency_value;        // e.g. 1
```

Use these fields to display context like "Delivered monthly" or "Every 3 months" directly in the cart row.

## Mixed cart guard

Mixed carts are not supported in the current release. If the cart contains both subscription and one-time items, disable the checkout CTA and show a clear explanation to the customer.

```typescript theme={null}
if (purchaseMode === "mixed") {
  // Disable checkout, show limitation message
}
```

<Note>
  If a customer wants to purchase a subscription item and a one-time item together, they need to use separate carts and complete them through their respective checkout flows.
</Note>

## Cart CTA

Change the cart's call-to-action label based on the current purchase mode to set the right expectation before checkout:

| Mode           | Suggested CTA                      |
| -------------- | ---------------------------------- |
| `one-time`     | "Proceed to checkout"              |
| `subscription` | "Proceed to subscription checkout" |
| `mixed`        | Disabled — show mixed cart message |

## Next step

When the customer proceeds from a subscription cart, complete the order through the [Subscription Checkout](/storefront/subscription-checkout) flow instead of the standard Medusa cart-complete route.