enable

Enables timer mocking for the specified timers.

Note: When you enable mocking for a specific timer, its associated clear function will also be implicitly mocked.

Note: Mocking Date will affect the behavior of the mocked timers as they use the same internal clock.

Example usage without setting initial time:

import { mock } from 'node:test';
mock.timers.enable({ apis: ['setInterval', 'Date'], now: 1234 });

The above example enables mocking for the Date constructor, setInterval timer and implicitly mocks the clearInterval function. Only the Date constructor from globalThis, setInterval and clearInterval functions from node:timers, node:timers/promises, and globalThis will be mocked.

Example usage with initial time set

import { mock } from 'node:test';
mock.timers.enable({ apis: ['Date'], now: 1000 });

Example usage with initial Date object as time set

import { mock } from 'node:test';
mock.timers.enable({ apis: ['Date'], now: new Date() });

Alternatively, if you call mock.timers.enable() without any parameters:

All timers ('setInterval', 'clearInterval', 'Date', 'setImmediate', 'clearImmediate', 'setTimeout', and 'clearTimeout') will be mocked.

The setInterval, clearInterval, setTimeout, and clearTimeout functions from node:timers, node:timers/promises, and globalThis will be mocked. The Date constructor from globalThis will be mocked.

If there is no initial epoch set, the initial date will be based on 0 in the Unix epoch. This is January 1st, 1970, 00:00:00 UTC. You can set an initial date by passing a now property to the .enable() method. This value will be used as the initial date for the mocked Date object. It can either be a positive integer, or another Date object.