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.
Trigger functions in javascript using Cron syntax.
Try it live on jsfiddle.
Croner
- Trigger functions in JavaScript using Cron syntax
- Pause, resume or stop execution efter a task is scheduled
- Find first date of next month, find date of next tuesday, etc.
- Works in Node.js >=4.0 (require and import)
- Works in browsers as standalone, UMD or ES-module.
- Experimental feature: Schedule in specific target timezones
- Includes TypeScript typings
Quick examples:
let job = Cron('* * * * * *', () => {
console.log('This will run every second');
});
let nextSunday = Cron('0 0 0 * * 7').next();
console.log(nextSunday.toLocaleDateString());
let msLeft = Cron('59 59 23 24 DEC *').next() - new Date();
console.log(Math.floor(msLeft/1000/3600/24) + " days left to next christmas eve");
More examples...
Installation
Node.js
npm install croner --save
import Cron from "croner";
const Cron = require("croner");
Browser
Manual
- Download latest zipball
- Unpack
- Grab
croner.min.js
(UMD and standalone) or croner.min.mjs
(ES-module) from the dist/ folder
CDN
To use as a UMD-module (stand alone, RequireJS etc.)
<script src="https://cdn.jsdelivr.net/npm/croner@4/dist/croner.min.js"></script>
To use as a ES-module
<script type="module">
import Cron from "https://cdn.jsdelivr.net/npm/croner@4/dist/croner.min.mjs";
</script>
Documentation
Full documentation available at hexagon.github.io/croner.
The short version:
Signature
Cron takes three arguments
var job = Cron("* * * * * *" , { maxRuns: 1 } , () => {} );
job.schedule(() => {});
let nextRun = job.next( previousRun );
let prevRun = job.previous( );
let msToNext = job.msToNext( previosRun );
let isRunning = job.running();
job.pause();
job.resume();
job.stop();
Options
Key | Default value | Data type | Remarks |
---|
maxRuns | Infinite | Number | |
timezone | undefined | String | Timezone in Europe/Stockholm format |
startAt | undefined | String | ISO 8601 formatted datetime (2021-10-17T23:43:00) in local or specified timezone |
stopAt | undefined | String | ISO 8601 formatted datetime (2021-10-17T23:43:00) in local or specified timezone |
paused | false | Boolean | If the job should be paused from start. |
Pattern
Field | Required | Allowed values | Allowed special characters | Remarks |
---|
Seconds | Optional | 0-59 | * , - / | |
Minutes | Yes | 0-59 | * , - / | |
Hours | Yes | 0-23 | * , - / | |
Day of Month | Yes | 1-31 | * , - / | |
Month | Yes | 1-12 or JAN-DEC | * , - / | |
Day of Week | Yes | 0-7 or SUN-MON | * , - / | 0 to 6 are Sunday to Saturday 7 is Sunday, the same as 0 |
Note: Weekday and month names are case insensitive. Both MON and mon works.
Examples
Expressions
Cron('0-4 */5 1,2,3 * JAN-MAR SAT', function () {
console.log('This will run the first five seconds every fifth minute');
console.log('of hour 1,2 and 3 every saturday in January to March.');
});
Find dates
let nextMonth = Cron('0 0 0 1 * *').next(),
nextSunday = Cron('0 0 0 * * 7').next(),
nextSat29feb = Cron("0 0 0 29 2 6").next();
console.log("First day of next month: " + nextMonth.toLocaleDateString());
console.log("Next sunday: " + nextSunday.toLocaleDateString());
console.log("Next saturday at 29th of february: " + nextSat29feb.toLocaleDateString());
With options
var job = Cron(
'* * * * *',
{
maxRuns: Infinity,
startAt: "2021-11-01T00:00:00",
stopAt: "2021-12-01T00:00:00",
timezone: "Europe/Stockholm"
},
function() {
console.log('This will run every minute, from 2021-11-01 to 2021-12-01 00:00:00 in Europe/Stockholm.');
}
);
Job controls
let job = Cron('* * * * * *', (self) => {
console.log('This will run every second. Pause on second 10. Resume on second 15. And quit on second 20.');
console.log('Current second: ', new Date().getSeconds());
console.log('Previous run: ' + self.previous());
console.log('Next run: ' + self.next());
});
Cron('10 * * * * *', {maxRuns: 1}, () => job.pause());
Cron('15 * * * * *', {maxRuns: 1}, () => job.resume());
Cron('20 * * * * *', {maxRuns: 1}, () => job.stop());
License
MIT