Fulfill orders safely

export async function handleConfirmedPayment(event) {
  if (event.type !== "payment.confirmed") return;
  const payment = event.data.object;
  const order = await orders.findByPaymentId(payment.id);
  if (!order || order.amountMinor !== payment.amountMinor || order.currency !== payment.currency) {
    throw new Error("payment does not match the order");
  }
  await orders.fulfillOnce(order.id, event.id);
}