timezone - Transform Epoch UTC to String EST using momentjs

Question

I have two input variables: an epoch time in UTC time zone and the name of the actual time zone. How do I get a formatted day/time using moment.js that would take in account the DST changes. I tried this code but it doesn't do the trick. What am I doing wrong, please?

var abs_time = 1611188219.277; // this is UTC coresponding to 1/21/2021 18:31:37 UTC
var timezone = "America/New_York"; // this the actual time zone

var mom = moment(abs_time * 1000).format();
var date_time = moment.tz(mom, timezone).format('ddd, MMM DD YYYY - HH:mm');
console.log(date_time);

//actual result: Thu, Jan 21 2021 - 18:31
//desired result: Thu, Jan 21 2021 - 13:31 - in the summer this should only be 4 hour difference

question from:https://stackoverflow.com/questions/65833933/transform-epoch-utc-to-string-est-using-momentjs

Answer 1

First, 1611188219.277 actually corresponds to 2021-01-21T00:16:59.277Z, not the time you gave in your question (assuming it is a Unix timestamp with seconds precision). This can be seen with the following code:

const d = new Date(1611188219.277 * 1000);
const s = d.toISOString();
console.log(s);