javascript cron can be used in node.js

cron.js

/*
    Added complex matches by Shimon Doodkin 2012
    Developed by Elijah Rutschman 2009 - http://elijahr.blogspot.com/2009/03/javascript-cron.html
*/
/*
a typical cron entry has either wildcards (*) or an integer:

            .---------------- minute (0 - 59) 
            | .-------------- hour (0 - 23)
            | | .------------ day of month (1 - 31)
            | | | .---------- month (1 - 12)
            | | | | .-------- day of week (0 - 6) (Sunday=0)
            | | | | |
            * * * * *
*/
//          m h d M w
//cron.add("* * * * *", function(){alert('cron job that runs every minute')})

var cron = {
  jobs : [],
  parse: function(a)
  {
   var active_at=a.split(',').map(function(i)
   {
    var z=i.split('/');
    var x=z[0].split('-');
    
    if(x[0] == "*") x[0]=-1;
    
    if(x.length==1)
     x.push(x[0]);
    
    x[2]=z.length===1?-1:z[1];
    // parsed array structure:
    x[0]=parseInt(x[0]);// 0 - from
    x[1]=parseInt(x[1]);// 1 - to
    x[2]=parseInt(x[2]);// 2 modulus 
    
    return x;
   });
   var modulo=a.length>1?a[1]:-1;
   return active_at;
  },
  match: function(a,b)
  {
   for(var c,b0,i=0;i<a.length;i++)
   {
    c=a[i];
    if( c[0]===-1 || ( b>=c[0] && b<=c[1] ) )
    {
     b0=b-c[0]; // make the modulo start from 1st miniture of from matched time, not first minute of from 0 minutes
     if( c[2]===-1 || b0===0 || b0%c[2]===0 )
      return true;
    }
   }
   return  false;
  },
  process : function() {
  var now = new Date();
  for (var i=0; i<cron.jobs.length; i++) {
   if ( cron.match(cron.jobs[i].minute, now.getMinutes()) )
    if ( cron.match(cron.jobs[i].hour, now.getHours())    )
     if ( cron.match(cron.jobs[i].date, now.getDate())    )
      if ( cron.match(cron.jobs[i].month, now.getMonth()) )
       if ( cron.match(cron.jobs[i].day, now.getDay())    )
        cron.jobs[i].run();
  }
  now = null;
 },
 "id" : 0,
 "start" : function() {
  cron.stop();
  cron.id = setInterval(function(){cron.process()},60000);
 },
 "stop" : function() {
  clearInterval(cron.id);
 },
 "add" : function(cronstring, fun) {
  var _Job = {};
  var items = cronstring.match(/^([0-9,\-\/]+|\*{1}|\*{1}\/[0-9]+)\s+([0-9,\-\/]+|\*{1}|\*{1}\/[0-9]+)\s+([0-9,\-\/]+|\*{1}|\*{1}\/[0-9]+)\s+([0-9,\-\/]+|\*{1}|\*{1}\/[0-9]+)\s+([0-9,\-\/]+|\*{1}|\*{1}\/[0-9]+)\s*$/);
  _Job.minute = cron.parse(items[1]);
  _Job.hour = cron.parse(items[2]);
  _Job.date = cron.parse(items[3]);
  _Job.month = cron.parse(items[4]);
  _Job.day = cron.parse(items[5]);
  _Job.run = fun;
  cron.jobs.push(_Job);
  _Job = null;
  items = null;
 }
}
cron.start();
//if(module&&exports)module.exports=cron; // i use it in node.js
// or
//exports.cron=cron; // i use it in node.js

/*
// when cron is not running:
// queue up some jobs to run
cron.add("* * * * *", function(){alert('cron job 1 just ran')})
cron.add("5 * * * *", function(){alert('cron job 2 just ran')})
cron.add("15 * * * *", function(){alert('cron job 3 just ran')})
cron.add("30 * * * *", function(){alert('cron job 4 just ran')})
cron.start();

// Cron already running, but we can add more jobs, no problem
cron.add("0 * * * *", function(){alert('cron job 5 just ran')})
cron.add("7 9 * * 1,2,3,4,5", function(){alert('at 9:07 of every morning from sunday to thursday')})
*/

/*
testing the rulls matching:
var x;
console.log( x=cron.parse("0,1,2,3,4") ) // ruls can be 1-2/3,3-4/5  many match options are seperated by comma. but no spacing in between
console.log( cron.match(x,3) );
*/

/// each place can be : [number or number-number or *]/[modulus],[number or number-number or *]/[modulus],...
//       *  any number
//       5  number is 5
//    2-10  number from 5 to 10
//     */3  every 3rd will run, - optionaly after the / comes modulus, modulus calulates reminder, if reminder is zero means it devides by that number exactly
//  2-10/3  between 5 to 10 every 3rd will run
//  
//  2-10,12-16  many matchs but no spacing in between
//  2-10/5,12-16/2,*/10  alot matchs example

Nice, small and lightweight.

Love it!