Croner

Trigger functions in javascript using Cron syntax.
Pause, resume or stop exection efter a task is scheduled.
Find first date of next month, find date of next tuesday, etc.
Schedule in other timezone than default.
Supports Node.js from 4.0 to current. Both require (commonjs) and import (module).
Supports browser use (UMD (standalone, requirejs etc.), ES-module)

Documented with JSDoc for intellisense, and include TypeScript typings.

<script src="https://cdn.jsdelivr.net/npm/croner@4/dist/croner.min.js"></script>

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

// What date is next sunday?
console.log(Cron('0 0 0 * * 7').next().toLocaleDateString());

Installation

Manual

Download latest zipball
Unpack
Grab croner.min.js (UMD) or croner.min.mjs (ES-module) from the dist/ folder

Node.js

npm install croner --save

// ESM Import
import Cron from "croner";

// ... or

// CommonJS Require

const Cron = require("croner");

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";

    // ... see usage section ...
</script>

... or a ES-module with import-map

<script type="importmap">
    {
        "imports": {
            "croner": "https://cdn.jsdelivr.net/npm/croner@4/dist/croner.min.mjs"
        }
    }
</script>
<script type="module">
    import Cron from 'croner';

    // ... see usage section ...
</script>

Examples

Minimalist scheduling

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

Find dates

// Find next month
let nextMonth = Cron('0 0 0 1 * *').next(),
    nextSunday = Cron('0 0 0 * * 7').next();

console.log("First day of next month: " +  nextMonth.toLocaleDateString());
console.log("Next sunday: " +  nextSunday.toLocaleDateString());

Minimalist scheduling with stepping and custom timezone

// Run a function every fifth second
Cron('*/5 * * * * *', { timezone: 'Europe/Stockholm' }, 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 job 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 * * * * *', { maxRuns: 5 });

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

Scheduling with controls

let scheduler = Cron('* * * * * *')

scheduler.schedule(function () {
    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: ' + scheduler.previous());
    console.log('Next run: ' + scheduler.next());
});

Cron('10 * * * * *', {maxRuns: 1}, () => scheduler.pause());
Cron('15 * * * * *', {maxRuns: 1}, () => scheduler.resume());
Cron('20 * * * * *', {maxRuns: 1}, () => scheduler.stop());

Full API

var scheduler = Cron( <string pattern> [, { startAt: <date|string>, stopAt: <date|string>, maxRuns: <integer>, timezone: <string> } ] [, <function job> ] )

scheduler.next( [ <date previous> ] );
scheduler.msToNext( [ <date previous> ] );
scheduler.previous();
scheduler.schedule( <fn job> );
scheduler.pause();
scheduler.resume();
scheduler.stop();

Pattern

┌──────────────── (optional) 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