Function emit

Emits pub/sub events to the event bus, allowing workflows to broadcast messages to external subscribers. Each entry in the events map is published as a separate message on the corresponding topic.

By default (config.once = true), events are emitted exactly once per workflow execution — the isSideEffectAllowed guard prevents re-emission on replay. Set config.once = false to emit on every re-execution (rarely needed).

Examples

import { Durable } from '@hotmeshio/hotmesh';

// Emit a domain event when an order is processed
export async function orderWorkflow(orderId: string): Promise<void> {
  const { processOrder } = Durable.workflow.proxyActivities<typeof activities>();
  const result = await processOrder(orderId);

  await Durable.workflow.emit({
    'order.completed': { orderId, total: result.total },
    'analytics.event': { type: 'order', orderId },
  });
}
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// Emit progress events during a long-running workflow
export async function batchWorkflow(items: string[]): Promise<void> {
  const { processItem } = Durable.workflow.proxyActivities<typeof activities>();

  for (let i = 0; i < items.length; i++) {
    await processItem(items[i]);
    await Durable.workflow.emit(
      { 'batch.progress': { completed: i + 1, total: items.length } },
      { once: false },  // emit on every execution (progress updates)
    );
  }
}
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