CODEWITHSUNDEEP
javascriptmomentjsdatetime-format
user1614862
user1614862

Reputation: 4149

How to change only timezone without modifying the time in momentz

I have date and time in 2016-06-21T10:00:00-07:00 format which represets 06/21/2016 5 PM in PST, I just want to change this to 06/21/2016 5 PM in EST and vice versa. How can I do it with momentz?

JSFiddle

debugger;
var dateTime = moment('2016-06-21T10:00:00-07:00');
var newDateTime = dateTime.clone();
  newDateTime.tz('US/Eastern');
//dateTime = dateTime.utc();
    console.log(dateTime.utcOffset());

   console.log(newDateTime.utcOffset());
  console.log(newDateTime.utcOffset() - dateTime.utcOffset());
                //console.log(utc.format());
    dateTime =          dateTime.add(newDateTime.utcOffset(), 'minutes');
console.log(dateTime.format());
console.log(new Date(Date.parse(dateTime.format())).toJSON());

EDIT:

given input = 2016-06-21T08:00:00-07:00 (PST)

expected output = 2016-06-21T08:00:00-04:00 (EST)

So when I convert that to UTC then it should become

2016-06-22T15:00:00Z for PST 2016-06-22T12:00:00Z for EST

Upvotes: 3

Views: 8596

Answers (2)

Sanjay
Sanjay

Reputation: 111

Checkout moment().utcOffset() You can pass in the offset as parameter to this function and the date would use that locale.

Assuming you know beforehand the utcOffsets required which in your case are -420 and -240 or -300(EST with DayLightSaving). Below can be done

var dateTime = moment('2016-06-21T10:00:00-07:00');
dateTime.utcOffset(-420).format();
"2016-06-21T10:00:00-07:00"
dateTime.utcOffset(-240).format()
"2016-06-21T13:00:00-04:00"

NOTE: With -04:00, it should 13:00:00 and not 07:00:00 - http://www.timeanddate.com/time/zones/est

EDIT: This answer was posted to the earlier version of question, where same time was needed in different timezones. If it is incorrect, kindly please elaborate on how it is. Thanks!

Upvotes: 1

Maggie Pint
Maggie Pint

Reputation: 2452

I think you are confused about how ISO8601 format works. This format always represents local time with a time zone offset. Thus 2016-06-21T10:00:00-07:00 represents June 21 2016 at 10 AM in a timezone that is currently UTC-7 (this could be US pacific, among many others).

It sounds like you want to take the local time, but put it in a new timezone. This opens up some interesting questions about why you are receiving the date in the format that you are. If the date is meant to be interpreted as an exact point on the global timeline, then the format you are receiving it in is good. If however, the date is meant to be interpreted as a local time (not relative to UTC), it might be worth considering the possibility that the format of the date needs to be changed at the source. For instance, if you are making an ajax request to an API, and it is returning a date in this format, but that date actually has no relationship to UTC, it would be good to try to change that API to only send the local time (without the offset). If you were able to do that, then the following code would work:

moment.tz('2016-06-21T10:00:00', 'America/New_York').format()
"2016-06-21T10:00:00-04:00"

If you are unable to do that, or if the date is meant to be interpreted as an exact point on the global timeline, but you wish to ignore that in your specific use case, that can be done. You will need to specify a parse format that ignores the timezone offset on your initial time stamp. The code would be as follows:

moment.tz('2016-06-21T10:00:00-07:00', 'YYYY-MM-DDTHH:mm:ss', 'America/New_York').format()
"2016-06-21T10:00:00-04:00"

You might benefit from the material in this blog post, as it covers how ISO8601 format works, and how all of moment's constructor functions work.

Upvotes: 7

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