Skip to content
Sayiir

Tutorial: Order Processing (Node.js)

Build an order processing pipeline that validates orders, charges payment and checks inventory in parallel, then parks until a shipping provider calls your webhook — resuming automatically to send the confirmation.

import { task, flow, branch, runDurableWorkflow, sendSignal, resumeWorkflow } from "sayiir";


interface Order {
  orderId: string;
  amount: number;
}


interface ShipmentEvent {
  trackingNumber: string;
  carrier: string;
}


const validateOrder = task("validate-order", (order: Order) => {
  if (order.amount <= 0) throw new Error("Invalid amount");
  return { ...order, validated: true as const };
});


const chargePayment = task("charge-payment", (order: Order) => {
  return { ...order, paymentId: `pay_${order.orderId}`, charged: true as const };
}, { timeout: "30s", retry: { maxAttempts: 3, initialDelay: "1s", backoffMultiplier: 2.0 } });


const checkInventory = task("check-inventory", (order: Order) => {
  return { ...order, inStock: true as const };
});


const workflow = flow<Order>("order-processing")
  .then(validateOrder)
  .fork([
    branch("payment", chargePayment),
    branch("inventory", checkInventory),
  ])
  .join("finalize", ([payment, inventory]) => ({
    orderId: payment.orderId,
    paymentId: payment.paymentId,
    inStock: inventory.inStock,
  }))
  .waitForSignal<ShipmentEvent>("shipping-wait", "shipment_dispatched", { timeout: "72h" })
  .then("send-confirmation", (shipment) =>
    `Order shipped via ${shipment.carrier}, tracking: ${shipment.trackingNumber}`)
  .build();

The workflow parks at waitForSignal — no workers are held. When the shipping provider hits your webhook, deliver the payload as a signal:

// POST /webhooks/shipping handler
sendSignal(body.orderId, "shipment_dispatched", {
  trackingNumber: body.trackingNumber,
  carrier: body.carrier,
}, backend);


const result = resumeWorkflow(workflow, body.orderId, backend);

The full example includes a working HTTP server that receives the webhook and resumes the workflow.

Full example: Order Processing (Node.js) Complete source code with webhook server and curl commands.

Next Steps

Section titled “Next Steps”