How to set date always to eastern time regardless

Question

I have a date given to me by a server in unix time: 1458619200000

NOTE: the other questions you have marked as "duplicate" don't show how to get there from UNIX TIME. I am looking for a specific example in javascript.

However, I find that depending on my timezone I'll have two different results:

d = new Date(1458619200000)
Mon Mar 21 2016 21:00:00 GMT-0700 (Pacific Daylight Time)

// Now I set my computer to Eastern Time and I get a different result.

d = new Date(1458619200000)
Tue Mar 22 2016 00:00:00 GMT-0400 (Eastern Daylight Time)

So how can I show the date: 1458619200000 ... to always be in eastern time (Mar 22) regardless of my computer's time zone?

Answer 1

You can easily take care of the timezone offset by using the getTimezoneOffset() function in Javascript. For example,

var dt = new Date(1458619200000);
console.log(dt); // Gives Tue Mar 22 2016 09:30:00 GMT+0530 (IST)

dt.setTime(dt.getTime()+dt.getTimezoneOffset()*60*1000);
console.log(dt); // Gives Tue Mar 22 2016 04:00:00 GMT+0530 (IST)

var offset = -300; //Timezone offset for EST in minutes.
var estDate = new Date(dt.getTime() + offset*60*1000);
console.log(estDate); //Gives Mon Mar 21 2016 23:00:00 GMT+0530 (IST)

Though, the locale string represented at the back will not change. The source of this answer is in this post. Hope this helps!

Answer 2

Moment.js (http://momentjs.com/timezone) is your friend.

You want to do something like this:

var d = new Date(1458619200000);
var myTimezone = "America/Toronto";
var myDatetimeFormat= "YYYY-MM-DD hh:mm:ss a z";
var myDatetimeString = moment(d).tz(myTimezone).format(myDatetimeFormat);

console.log(myDatetimeString); // gives me "2016-03-22 12:00:00 am EDT"