How to parse calendar file dates with JavaScript?

Question

We need to use JavaScript on the browser to read and parse calendar files (.ics) (also called iCal formats). I wrote a custom function to read these values and then use the JavaScript Date() function to make a data object.

Is any easier and better way to do this? Please look at my function (below), your comments would be welcome.

A typical date value from an .ics file looks like this:

DTSTART:20110914T184000Z

Need to break it apart at the colon, so:

var strData = 'DTSTART:20110914T184000Z'
var x = strData.indexOf(":");
var strVal = strData.slice(x + 1 );

next, call a function that returns a date object:

var dateObj = calenDate(strVal);

//resulting dateObj value: Fri Oct 14 2011 18:40:00 GMT-0400 (Eastern Daylight Time)

Here is the function that parses the date.

function calenDate(icalStr)  {
    // icalStr = '20110914T184000Z'             
    var strYear = icalStr.substr(0,4);
    var strMonth = icalStr.substr(4,2);
    var strDay = icalStr.substr(6,2);
    var strHour = icalStr.substr(9,2);
    var strMin = icalStr.substr(11,2);
    var strSec = icalStr.substr(13,2);

    var oDate =  new Date(strYear,strMonth, strDay, strHour, strMin, strSec)

return oDate;
}

I think something is wrong since it is getting the month wrong.

Answer 1

For some odd reason the month parameter is zero-based (reference).

Change this line in your function.

var strMonth = icalStr.substr(4,2);

to this:

var strMonth = parseInt(icalStr.substr(4,2),10)-1;

See working demo on jsFiddle: http://jsfiddle.net/cTkTQ/