@chuxingpay/cron-parser

cron-parser
================
> Fork from harrisiirak/cron-parser
> update feature: add year options support


Node.js library for parsing crontab instructions. It includes support for timezones and DST transitions.

Setup
========
``bash
npm install cron-parser
`

Supported format
========

`
*
┬ ┬ ┬ ┬ ┬ ┬ ┬
│ │ │ │ │ | |
│ │ │ │ │ | └ year (0-9999)
│ │ │ │ │ └───── day of week (0 - 7) (0 or 7 is Sun)
│ │ │ │ └────────── month (1 - 12)
│ │ │ └─────────────── day of month (1 - 31)
│ │ └──────────────────── hour (0 - 23)
│ └───────────────────────── minute (0 - 59)
└────────────────────────────── second (0 - 59, optional)
`

Supports mixed use of ranges and range increments (L and W characters are not supported currently). See tests for examples.

Usage
========

Simple expression.

`javascript
var parser = require('cron-parser');

try {
var interval = parser.parseExpression('0 /2 ');

console.log('Date: ', interval.next().toString()); // Sat Dec 29 2012 00:42:00 GMT+0200 (EET)
console.log('Date: ', interval.next().toString()); // Sat Dec 29 2012 00:44:00 GMT+0200 (EET)

console.log('Date: ', interval.prev().toString()); // Sat Dec 29 2012 00:42:00 GMT+0200 (EET)
console.log('Date: ', interval.prev().toString()); // Sat Dec 29 2012 00:40:00 GMT+0200 (EET)
} catch (err) {
console.log('Error: ' + err.message);
}

`

Iteration with limited timespan. Also returns ES6 compatible iterator (when iterator flag is set to true).

`javascript
var parser = require('cron-parser');

var options = {
currentDate: new Date('Wed, 26 Dec 2012 12:38:53 UTC'),
endDate: new Date('Wed, 26 Dec 2012 14:40:00 UTC'),
iterator: true
};

try {
var interval = parser.parseExpression('0 /22 ', options);

while (true) {
try {
var obj = interval.next();
console.log('value:', obj.value.toString(), 'done:', obj.done);
} catch (e) {
break;
}
}

// value: Wed Dec 26 2012 14:44:00 GMT+0200 (EET) done: false
// value: Wed Dec 26 2012 15:00:00 GMT+0200 (EET) done: false
// value: Wed Dec 26 2012 15:22:00 GMT+0200 (EET) done: false
// value: Wed Dec 26 2012 15:44:00 GMT+0200 (EET) done: false
// value: Wed Dec 26 2012 16:00:00 GMT+0200 (EET) done: false
// value: Wed Dec 26 2012 16:22:00 GMT+0200 (EET) done: true
} catch (err) {
console.log('Error: ' + err.message);
}

`

Timezone support

`javascript
var parser = require('cron-parser');

var options = {
currentDate: '2016-03-27 00:00:01',
tz: 'Europe/Athens'
};

try {
var interval = parser.parseExpression('0 0 *', options);

console.log('Date: ', interval.next().toString()); // Date: Sun Mar 27 2016 01:00:00 GMT+0200
console.log('Date: ', interval.next().toString()); // Date: Sun Mar 27 2016 02:00:00 GMT+0200
console.log('Date: ', interval.next().toString()); // Date: Sun Mar 27 2016 04:00:00 GMT+0300 (Notice DST transition)
} catch (err) {
console.log('Error: ' + err.message);
}
`

Options
========

currentDate* - Start date of the iteration
endDate* - End date of the iteration

currentDate and endDate accept string, integer and Date as input.

In case of using string as input, not every string format accepted
by the Date constructor will work correctly. The supported formats are: ISO8601 and the older
ASP.NET JSON Date format. The reason being that those are the formats accepted by the
moment library which is being used to handle dates.

Using Date as an input can be problematic specially when using the tz option. The issue being that, when creating a new Date object without
any timezone information, it will be created in the timezone of the system that is running the code. This (most of times) won't be what the user
will be expecting. Using one of the supported string formats will solve the issue(see timezone example).

iterator* - Return ES6 compatible iterator object
utc* - Enable UTC
tz* - Timezone string. It won't be used in case utc` is enabled