zone.parse(timestamp); // 480
Parse an offset for a timestamp constructed from
Date.UTC in that zone.
This is what Moment Timezone uses to parse input into a time zone. The process is conceptually similar to the following.
Assume we want to find the exact moment of
March 19 2014 8:30 am in New York.
Because the offset varies between
-05:00 in New York, we don't know
what the offset was on March 19th.
Instead, we create a timestamp in UTC and pass that to
zone.parse, which will
return the offset at that time.
var zone = moment.tz.zone('America/New_York'); zone.parse(Date.UTC(2012, 2, 19, 8, 30)); // 240
This is the code that handles the cases referenced in the Parsing Ambiguities section above.
var zone = moment.tz.zone('America/New_York'); zone.parse(Date.UTC(2012, 2, 11, 1, 59)); // 300 zone.parse(Date.UTC(2012, 2, 11, 2, 0)); // 240