timers/promises

The timers/promises API provides an alternative set of timer functions that return Promise objects. The API is accessible via require('node:timers/promises').

import {
  setTimeout,
  setImmediate,
  setInterval,
} from 'node:timers/promises';

Usage in Deno

import * as mod from "node:timers/promises";

function setImmediate

Usage in Deno

import { setImmediate } from "node:timers/promises";

setImmediate<T = void>(

value?: T,

options?: TimerOptions,
): Promise<T>

import {
  setImmediate,
} from 'node:timers/promises';

const res = await setImmediate('result');

console.log(res);  // Prints 'result'

Type Parameters

T = void

Parameters

value: T

optional

A value with which the promise is fulfilled.

options: TimerOptions

optional

Return Type

Promise<T>

function setInterval

Usage in Deno

import { setInterval } from "node:timers/promises";

setInterval<T = void>(

delay?: number,

value?: T,

options?: TimerOptions,
): AsyncIterator<T>

Returns an async iterator that generates values in an interval of delay ms. If ref is true, you need to call next() of async iterator explicitly or implicitly to keep the event loop alive.

import {
  setInterval,
} from 'node:timers/promises';

const interval = 100;
for await (const startTime of setInterval(interval, Date.now())) {
  const now = Date.now();
  console.log(now);
  if ((now - startTime) > 1000)
    break;
}
console.log(Date.now());

Type Parameters

T = void

Parameters

delay: number

optional

The number of milliseconds to wait between iterations. Default: 1.

value: T

optional

A value with which the iterator returns.

options: TimerOptions

optional

Return Type

AsyncIterator<T>

function setTimeout

Usage in Deno

import { setTimeout } from "node:timers/promises";

setTimeout<T = void>(

delay?: number,

value?: T,

options?: TimerOptions,
): Promise<T>

import {
  setTimeout,
} from 'node:timers/promises';

const res = await setTimeout(100, 'result');

console.log(res);  // Prints 'result'

Type Parameters

T = void

Parameters

delay: number

optional

The number of milliseconds to wait before fulfilling the promise. Default: 1.

value: T

optional

A value with which the promise is fulfilled.

options: TimerOptions

optional

Return Type

Promise<T>

interface Scheduler

Usage in Deno

import { type Scheduler } from "node:timers/promises";

Methods

wait(

delay: number,

options?: { signal?: AbortSignal;  },
): Promise<void>

An experimental API defined by the Scheduling APIs draft specification being developed as a standard Web Platform API.

Calling timersPromises.scheduler.wait(delay, options) is roughly equivalent to calling timersPromises.setTimeout(delay, undefined, options) except that the ref option is not supported.

import { scheduler } from 'node:timers/promises';

await scheduler.wait(1000); // Wait one second before continuing

yield(): Promise<void>

An experimental API defined by the Scheduling APIs draft specification being developed as a standard Web Platform API.

Calling timersPromises.scheduler.yield() is equivalent to calling timersPromises.setImmediate() with no arguments.

variable scheduler

Usage in Deno

import { scheduler } from "node:timers/promises";

Type

Scheduler