I think I have a simpler solution — set the initial date to the epoch and add UTC units. Say you have a UTC epoch var stored in seconds. How about 1234567890
. To convert that to a proper date in the local time zone:
var utcSeconds = 1234567890;
var d = new Date(0); // The 0 there is the key, which sets the date to the epoch
d.setUTCSeconds(utcSeconds);
d
is now a date (in my time zone) set to Fri Feb 13 2009 18:31:30 GMT-0500 (EST)