Return next localized date for countdown timer

Question

I have this code that does a calculation to find the a localized UTC time. Based on that UTC time there's another function that will calculate a next event date and time for me. If the time is between Sunday @ 12 and Wednesday @ 8 it will give me wednesdays event date, otherwise it will give me the next event date on Sunday. I then take that calculated date, split it apart and feed it in as parameter to a countdown timer.

I'm wondering if there's a more optimize way to do this, particularly with the conditional statement and where I split apart the time into parameters.

$(function () {
// Calculate the time locally
function calcLocalizedTime() {
    var d = new Date(); // Date for current location
    var utc = d.getTime() + (d.getTimezoneOffset() * 60000); // convert to msec add local time zone offset get UTC time in msec
    var nd = new Date(utc + (3600000 * -5));
    return nd; // return localized datetime
}

// Calculate the next Webcast DateTime
function calcNextWebCast(date) {
    var localizedTime = new Date(date||new Date()); // localized datetime
    var nextDate = new Date(date||new Date()); // Next webcast datetime object
    var today = localizedTime.getDay() + '' + localizedTime.getHours(); // format localized datetime for comparison

    if (today >= 012 && today <=320 ) { // is today between Sun @ 12 or Wednesday @ 8
        nextDate.setDate(nextDate.getDate() + (3 - 1 - nextDate.getDay() + 7) % 7 + 1);
        nextDate.setHours(20,0,0,0);
    } else {
        nextDate.setDate(nextDate.getDate() + (3 - 4 - nextDate.getDay() + 7) % 7 + 1);
        nextDate.setHours(12,0,0,0);
    }

    return nextDate;
}

var localizedTime = calcLocalizedTime();
var nextWebCast = calcNextWebCast(localizedTime);
var m = nextWebCast.getMonth() + 1;
var d = nextWebCast.getDate();
var y = nextWebCast.getFullYear();
var hh = nextWebCast.getHours();
var mm = nextWebCast.getMinutes();

$('#defaultCountdown').countdown({until: $.countdown.UTCDate(-5, y, m-1, d, hh, mm)});

});

Answer 1

I'm wondering if there's a more optimize way to do this, particularly with the conditional statement and where I split apart the time into parameters.

Use a dispatch table to replace the conditional statement and a regexp to replace the range:

function foo(nextDate)
 {
 calcNextWebCast.nextDate.setDate(calcNextWebCast.nextDate.getDate() + (3 - 1 - nextDate.getDay() + 7) % 7 + 1);
 calcNextWebCast.nextDate.setHours(20,0,0,0);
 }

function bar(nextDate)
 {
 calcNextWebCast.nextDate.setDate(calcNextWebCast.nextDate.getDate() + (3 - 4 - nextDate.getDay() + 7) % 7 + 1);
 calcNextWebCast.nextDate.setHours(12,0,0,0);
 }


function calcNextWebCast(date) {
 calcNextWebCast.nextDate = new Date(date||new Date()); // Next webcast datetime object

 var localizedTime = new Date(date||new Date()); // localized datetime
 var today = localizedTime.getDay() + '' + localizedTime.getHours(); // format localized datetime for comparison

 var range = "012|[0][1][3-9]|[0][2-9][0-9]|[1-2][0-9][0-9]|[3][0-1][0-9]|320";

 var datemap = { "true":foo, "false":bar }

 var jump = RegExp(range).test(today);

 var go = datemap[jump];

 go();

 return nextDate;
 }

References

• Custom Events in JavaScript

• Matching Numeric Ranges with a Regular Expression