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Class: Trigger<T>

A PromiseLike helper which exposes its resolve and reject methods.

Trigger is CancellationScope-aware: it is linked to the current scope on construction and throws when that scope is cancelled.

Useful for e.g. waiting for unblocking a Workflow from a Signal.

Example​

import { defineSignal, setHandler, sleep, Trigger } from '@temporalio/workflow';

const completeUserInteraction = defineSignal('completeUserInteraction');

export async function waitOnUser(userId: string): Promise<void> {
  const userInteraction = new Trigger<boolean>();

  // programmatically resolve Trigger
  setHandler(completeUserInteraction, () => userInteraction.resolve(true));

  const userInteracted = await Promise.race([userInteraction, sleep('30 days')]);
  if (!userInteracted) {
    await sendReminderEmail(userId);
  }
}

Type Parameters​

T​

T

Implements​

  • PromiseLike<T>

Constructors​

Constructor​

new Trigger<T>(): Trigger<T>

Returns​

Trigger<T>

Properties​

reject​

readonly reject: (reason?) => void

Parameters​

reason?​

any

Returns​

void

resolve​

readonly resolve: (value) => void

Parameters​

value​

T | PromiseLike<T>

Returns​

void

Methods​

then()​

then<TResult1, TResult2>(onfulfilled?, onrejected?): PromiseLike<TResult1 | TResult2>

Attaches callbacks for the resolution and/or rejection of the Promise.

Type Parameters​

TResult1​

TResult1 = T

TResult2​

TResult2 = never

Parameters​

onfulfilled?​

((value) => TResult1 | PromiseLike<TResult1>) | null

The callback to execute when the Promise is resolved.

onrejected?​

((reason) => TResult2 | PromiseLike<TResult2>) | null

The callback to execute when the Promise is rejected.

Returns​

PromiseLike<TResult1 | TResult2>

A Promise for the completion of which ever callback is executed.

Implementation of​

PromiseLike.then