How to change a timezone to another timezone in netsuite while using restlet

Question

I am sending lastmodified date via url in restlet but the problem is I have to modify the date based on user's timezone where restlet is deployed. SO, I need to change the timezone to his timezone before putting date in last modified filter. The problem I am facing is when I am using the new Date() function it is always changing the timezone to PST time zone instead of users time zone. Have a look at the question.

function getCompanyCurrentDateTime(UTCtime) { 
    var UTCtime = UTCtime; // Utc time is in milliseconds 
    var companyTimeZone = nlapiLoadConfiguration('companyinformation').getFieldText('timezone');
    nlapiLogExecution("DEBUG", "companyTimeZone",companyTimeZone );
    var timeZoneOffSet = (companyTimeZone.indexOf('(GMT)') == 0) ? 0 : new Number(companyTimeZone.substr(4, 6).replace(/\+|:00/gi, '').replace(/:30/gi, '.5'));
    nlapiLogExecution("DEBUG", "timeZoneOffSet",timeZoneOffSet ); // timezone offset is in hours and minutes 
    var timeZoneOffSetStr = timeZoneOffSet.toString();
    var timeZoneOffSetRes = timeZoneOffSetStr.split(".");
    var timeZoneOffSetMilli = Number(timeZoneOffSetRes[0])*3600*1000 + Number(timeZoneOffSetRes[1])*60*1000;
    nlapiLogExecution("DEBUG", "timeZoneOffSetMilli",timeZoneOffSetMilli );
    var NewcompanyDateTime = new Date(UTCtime + (timeZoneOffSetMilli));
    nlapiLogExecution("DEBUG", "NewcompanyDateTime",NewcompanyDateTime );
    return NewcompanyDateTime;
}

Answer 1

I use momentjs as library for timezone corrections than doing manual offset calculations.

You will need to include momentjs and its timezone data in your script as library

//I believe you already know code using nlapiLoadConfiguration on getting timezone and date format
moment(new Date()).tz(getComapnyTimeZone()).format(getCompanyDateFormat());
moment(new Date()).tz(getComapnyTimeZone()).format(getCompanyDateTimeFormat());

Answer 2

If the argument UTCtime is already universal standard, and you want to convert it to the browser's local time, you may want to try something like

function localTime(UTCtime)  // convert UTC in ms to local time in ms
{ return UTCtime + (new Date()).getTimezoneOffset() * 60 * 1000;
}

As noted in the question, getCompanyCurrentDateTime(UTCtime) will convert UTCtime to PST just as long as company time uses PST and that is the offset you apply to the parameter value!