Node Cron

The node-cron module is tiny task scheduler in pure JavaScript for node.js based on GNU crontab. This module allows you to schedule task in node.js using full crontab syntax.

Need a job scheduler with support for worker threads and cron syntax? Try out the Bree job scheduler!

Getting Started

Install node-cron using npm:

npm install --save node-cron

Import node-cron and schedule a task:

commonjs

const cron = require('node-cron');

cron.schedule('* * * * *', () => {
  console.log('running a task every minute');
});

es6 (module)

import cron from 'node-cron';

cron.schedule('* * * * *', () => {
  console.log('running a task every minute');
});

Cron Syntax

This is a quick reference to cron syntax and also shows the options supported by node-cron.

Allowed fields

 # ┌────────────── second (optional)
 # │ ┌──────────── minute
 # │ │ ┌────────── hour
 # │ │ │ ┌──────── day of month
 # │ │ │ │ ┌────── month
 # │ │ │ │ │ ┌──── day of week
 # │ │ │ │ │ │
 # │ │ │ │ │ │
 # * * * * * *

Allowed values

field	value
second	0-59
minute	0-59
hour	0-23
day of month	1-31
month	1-12 (or names)
day of week	0-7 (or names, 0 or 7 are sunday)

Using multiples values

You may use multiples values separated by comma:

import cron from 'node-cron';

cron.schedule('1,2,4,5 * * * *', () => {
  console.log('running every minute 1, 2, 4 and 5');
});

Using ranges

You may also define a range of values:

import cron from 'node-cron';

cron.schedule('1-5 * * * *', () => {
  console.log('running every minute to 1 from 5');
});

Using step values

Step values can be used in conjunction with ranges, following a range with '/' and a number. e.g: 1-10/2 that is the same as 2,4,6,8,10. Steps are also permitted after an asterisk, so if you want to say “every two minutes”, just use */2.

import cron from 'node-cron';

cron.schedule('*/2 * * * *', () => {
  console.log('running a task every two minutes');
});

Using names

For month and week day you also may use names or short names. e.g:

import cron from 'node-cron';

cron.schedule('* * * January,September Sunday', () => {
  console.log('running on Sundays of January and September');
});

Or with short names:

import cron from 'node-cron';

cron.schedule('* * * Jan,Sep Sun', () => {
  console.log('running on Sundays of January and September');
});

Cron methods

Schedule

Schedules given task to be executed whenever the cron expression ticks.

Arguments:

expression string: Cron expression
function Function: Task to be executed
options Object: Optional configuration for job scheduling.

Options

scheduled: A boolean to set if the created task is scheduled. Default true;
recoverMissedExecutions: A boolean to set if the created task should be able to recover missed executions. Default false;
timezone: The timezone that is used for job scheduling. See IANA time zone database for valid values, such as Asia/Shanghai, Asia/Kolkata, America/Sao_Paulo.

Example:

 import cron from 'node-cron';

 cron.schedule('0 1 * * *', () => {
   console.log('Running a job at 01:00 at America/Sao_Paulo timezone');
 }, {
   scheduled: true,
   timezone: "America/Sao_Paulo"
 });

ScheduledTask methods

Start

Starts the scheduled task.

import cron from 'node-cron';

const task = cron.schedule('* * * * *', () =>  {
  console.log('stopped task');
}, {
  scheduled: false
});

task.start();

Stop

The task won't be executed unless re-started.

import cron from 'node-cron';

const task = cron.schedule('* * * * *', () =>  {
  console.log('will execute every minute until stopped');
});

task.stop();

Validate

Validate that the given string is a valid cron expression.

import cron from 'node-cron';

const valid = cron.validate('59 * * * *');
const invalid = cron.validate('60 * * * *');

Naming tasks

You can name your tasks to make it easier to identify them in the logs.

import cron from 'node-cron';

const task = cron.schedule('* * * * *', () =>  {
  console.log('will execute every minute until stopped');
}, {
  name: 'my-task'
});

List tasks

You can list all the tasks that are currently running.

import cron from 'node-cron';

const tasks = cron.getTasks();

for (let [key, value] of tasks.entries()) {
  console.log("key", key)
  console.log("value", value)
}

value is an object with the following properties:

_events
_eventsCount
_maxListeners
options
_task
etc...

Issues

Feel free to submit issues and enhancement requests here.

Contributing

In general, we follow the "fork-and-pull" Git workflow.

Fork the repo on GitHub;
Commit changes to a branch in your fork;
Pull request "upstream" with your changes;

NOTE: Be sure to merge the latest from "upstream" before making a pull request!

Please do not contribute code you did not write yourself, unless you are certain you have the legal ability to do so. Also ensure all contributed code can be distributed under the ISC License.