croner

What is croner?

The croner npm package is a high-performance task scheduler for Node.js that allows you to run tasks at specific times or intervals. It is designed to be a drop-in replacement for the 'cron' package with additional features and improvements.

What are croner's main functionalities?

Simple cron job scheduling

This feature allows you to schedule a task to run at intervals defined by the cron syntax. In the provided code sample, a job is scheduled to run every 5 seconds.

const { Cron } = require('croner');

const job = Cron('*/5 * * * * *', () => {
  console.log('This will run every 5 seconds');
});

One-time execution

This feature allows you to schedule a task to run once at a specific time in the future. The code sample schedules a job to run once after 10 seconds.

const { Cron } = require('croner');

const job = Cron(new Date(Date.now() + 10000), () => {
  console.log('This will run once after 10 seconds');
});

Stopping a job

This feature allows you to stop a scheduled job. In the code sample, a job is scheduled to run every 5 seconds but is stopped after 15 seconds.

const { Cron } = require('croner');

const job = Cron('*/5 * * * * *', () => {
  console.log('This job will be stopped.');
});

setTimeout(() => {
  job.stop();
}, 15000);

Timezone support

This feature allows you to schedule jobs according to a specific timezone. The code sample schedules a job to run at 10:30 AM in the 'America/New_York' timezone.

const { Cron } = require('croner');

const job = Cron('0 30 10 * * *', () => {
  console.log('This will run at 10:30 AM in the America/New_York timezone.');
}, { timezone: 'America/New_York' });

Other packages similar to croner

node-schedule

node-schedule is a flexible cron-like and not-cron-like job scheduler for Node.js. It allows you to schedule jobs using both cron-style and human-readable syntax. It is similar to croner but offers a different API and additional scheduling features like scheduling jobs with JavaScript Date objects.

agenda

agenda is a job scheduling library for Node.js that uses MongoDB for persisting job data. It is more suitable for distributed or long-running job tasks. Unlike croner, which focuses on in-memory cron job scheduling, agenda provides persistence and is better suited for applications that require job recovery and failover capabilities.

bull

bull is a Redis-based queue system for Node.js. It is designed for handling distributed jobs and messages in Node.js applications. While croner is used for scheduling tasks, bull is more focused on job queuing, processing, and concurrency, making it suitable for more complex job handling scenarios.

README

Croner

Pure JavaScript minimal isomorphic cron parser and scheduler. Or simply speaking - setInterval on steroids.

Supports Node.js, requirejs, es-module and stand alone usage.

Documented with JSDoc for intellisense, and complete TypeScript typings for type checking.

<script src="https://cdn.jsdelivr.net/npm/croner@1.1.31/dist/croner.min.js"></script>

// Run a function each second
Cron('* * * * * *', function () {
	console.log('This will run every second');
});

Installation

Node.js

npm install croner

CDN

Copy and paste one of the following script tags.

Minified normal module (umd)

<script src="https://cdn.jsdelivr.net/npm/croner@1.1.31/dist/croner.min.js"></script>

Minified ESM-module

See usage-section for more examples, including ESM usage.

Manual (server/client)

• Download latest zipball
• Unpack
• Grab croner.min.js or croner.min.mjs from the dist/ folder

Usage

Node.js/CommonJS

var Cron = require('croner');

Cron('* * * * * *', function () {
	console.log('This will run every second');
});

Browser ESM

Import croner.min.mjs from cdn or manually, see installation section above.

<script type="module">
import Cron from 'https://cdn.jsdelivr.net/npm/croner@1.1.31/dist/croner.min.mjs';

Cron('* * * * * *', () => {
	console.log('This will run every second');
});
</script>

Browser ESM with import-maps

Import croner.min.mjs from cdn or manually, see installation section above.

<script type="importmap">
{
  "imports": {
    "croner": "https://cdn.jsdelivr.net/npm/croner@1.1.31/dist/croner.min.mjs"
  }
}
</script>
<script type="module">
import Cron from 'croner';

Cron('* * * * * *', () => {
	console.log('This will run every second');
});
</script>

Browser, stand-alone

Include croner.min.js fron cdn or manually, see installation section above. Croner registers itself globally as 'Cron'.

// Run a function each second
Cron('* * * * * *', function () {
	console.log('This will run every second');
});

Browser, require.js

Include croner.min.js in your preferred way, it will register itself as a require.js module.

define(["croner"], function(Cron) {

	Cron('* * * * * *', function () {
		console.log('This will run every second');
	});

});

Examples

Minimalist scheduling

// Run a function each second
Cron('* * * * * *', function () {
	console.log('This will run every second');
});

Minimalist scheduling with stepping

// Run a function every fifth second
Cron('*/5 * * * * *', function () {
	console.log('This will run every fifth second');
});

Minimalist scheduling with range

// Run a function the first five seconds of a minute
Cron('0-4 * * * * *', function () {
	console.log('This will run the first five seconds every minute');
});

Minimalist scheduling with options

// Run a function each second, limit to five runs
Cron('* * * * * *', { maxRuns: 5 }, function () {
	console.log('This will run each second, but only five times.');
});

Minimalist scheduling with controls

// Run a function each second, get reference to job
var job = Cron('* * * * * *', function () {
	console.log('This will run each second.');
});

// Pause job
job.pause();

// Resume job
job.resume();

// Stop job
job.stop();

Basic scheduling

// Run every minute
var scheduler = Cron('0 * * * * *');

scheduler.schedule(function() {
	console.log('This will run every minute');
});

Scheduling with options

// Run every minute
var scheduler = Cron('0 * * * * *');

// Schedule with options (all options are optional)
scheduler.schedule({ maxRuns: 5 }, function() {
	console.log('This will run every minute.');
});

Scheduling with controls

// Run every minute
var scheduler = Cron('0 * * * * *');

// Schedule with options (all options are optional)
var job = scheduler.schedule({ maxRuns: 5 }, function() {
	console.log('This will run every minute.');
});

// Pause job
job.pause();

// Resume job
job.resume();

// Stop job
job.stop();

Full API

var o = Cron( <string pattern> [, <object options>] [, <function callback> ] );

// If Cron is initialized without a scheduled function, cron itself is returned
// and the following member functions is available.
o.next( [ <date previous> ] );
o.msToNext();
o.previous();

// If Cron is initialized _with_ a scheduled function, the job is retured instead.
// Otherwise you get a reference to the job when scheduling a new job.
var job = o.schedule( [ { startAt: <date>, stopAt: <date>, maxRuns: <integer> } ,] callback);

// These self-explanatory functions is available to control the job
job.pause();
job.resume();
job.stop();

Pattern

┌──────────────── second (0 - 59)
│ ┌────────────── minute (0 - 59)
│ │ ┌──────────── hour (0 - 23)
│ │ │ ┌────────── day of month (1 - 31)
│ │ │ │ ┌──────── month (1 - 12)
│ │ │ │ │ ┌────── day of week (0 - 6) 
│ │ │ │ │ │       (0 to 6 are Sunday to Saturday; 7 is Sunday, the same as 0)
│ │ │ │ │ │
* * * * * *

License

MIT