timexe

Timexe - A Cron-like Timer and scheduler witn milliseconds resolution

Also works in a browser

Features

• Milliseconds resolution
• Improved cron-like syntax
• Recalculate long running timers, to improve accuracy
• No dependencies
• Works both for node JS and browser inclusion
• Time expressions include ranges, sets, timestamps, weekdays, yeardays and more

Precission

At present it seems to have an accuracy within 2 ms in node and up to 25 ms i most browsers. It seems that execution is defered somewhat during process load.

Example

To add a timed job every day at noon:

timexe(”* * * 12”, function(){console.log(“hello - it is noon again”)});

The time expression syntax is like cron, but in reverse order: starting with year, month... (where as cron start with minutes, hours...) plus some enhancements.

Time expression Syntax

---

The basic syntax is a series of fields specifying the time(s):

<year> <month> <day> <hour> <minute> <second> <millisecond> <microsecond> ...

or a time stamp.

Each field contain wild-cards, ranges, sets, not flags and every flags. Plus some special flags for year days and week days.

The epoch timestamp is seconds since 1970-01-01 UTC with fractions of second as decimal part:

@<epoch>[.<faction of second>]

Field syntax: [!][-]<value>[-<value>]|[,<value>] | /<value> | *

space : field separator
*     : all values. Flags will be ignored.
!     : not
/     : every (can not be combined with ! and range)
-     : Negative values are counted back from the maximum value
a-b   : range. both a and b included.
a,b   : set of values

Day field can have the one of the following flags as well
y: day of year
w: day of week 1-7  (1 is Monday)

Unspecified minor fields are assumed to have the lowest possible value

Note:

• Time expression are in local time where as time stamps are in UTC
• Month and weekday use another offset then the javascript Date function:
• Month 1 is January
• Week day 1-7 starting with Monday

Examples og timer expressions:

Time	Time expression
Every hour	* * * *
Every day at noon	* * * 12
Every 3th Hour on work days	* * w1-5 /3
Once at a specific epoch time	@1422821601.123
Once at a specific time	2014 5 13 18 53 7 300 230
2th to last day of the month at noon	* * -2 12
3th last day of the year	* * y-3
3 times an hour during work time	* * w1-5 9-17 0,20,40
Every morning at 7:30 but not on weekends	* * !6-7 7 30
Every 10 minutes in the day time	* * * 8-18 /10

API

---

timexe(timeExpression, callBack [,parameterToCallBack])

Returns a result object:

{
  result: “ok” or null
  error:  A failure explanation or null
  id:	  integer used to identify the timer
}

timexe.remove(id)

where id is the value returned from timexe

Returns a result object:

{
  result: “ok” or null
  error:  A failure explanation or null
}

timexe.get([id])

where the optional id is the value returned from timexe

Returnes either a chronos timer object if id is given, or an array of all active timer objects.

Settings

timexe.timeResolution (integer)

This is the minimum time resolution for an expression. Minimum value is 1 ms. default is 2 ms. This should be more the the execution time and delays do to load, of the intepreter.

timexe.maxTimerDelay (integer)

Maximum run time of a setTimeout call. Some javascripts engines cant handle more then 32 bit = 0x7FFFFFF. thats about 28 days. default is 86400000 = 1 day. When this time have elapsed, the time expression are reevaluated.

With node JS

---

Install

$ npm install timexe

Use

var timexe = require('timexe');

// Add
var res1=timexe(”* * * 12”, function(){console.log(“hello wolrd”)});

// Remove
var res2=timexe.remove(res1.id);

With HTML & javascript

---

Install

Copy files to folder.

Use

<script type="text/JavaScript" src="timexe.js"></script>
<script>
// Add
var res1=timexe(”* * * 12”, function(){alert(“hello wolrd”)});

// Remove
var res2=timexe.remove(res1.id);
</script>

Change log

0.9.18 Documentation update. 0.9.14 A quick code review. No bugs repported for 2 years. 0.9.13 Minor changes to timex.js 0.9.12 Minor changes to comments and reamne.md 0.9.11 Minor changes to comments and reamne.md 0.9.10 Adapted example to runkit 0.9.9 Minor bugfix. timexe.list made into a regular array.

####Help Please don't hesitate to submit an issue on github! It's the only way to make it better.

But please be prepared to present a test case.

Contributions of almost any kind are welcome.