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Moment.js resolve timezone offset

I'm working in an Angular 6 front end and receive from another system time stamps which have no time zones (C# backend, DateTime). I suspect that javascript is automatically adding the local time zone to Date objects.
Example:
Receiving from backend: 2018-10-15T07:53:00.000Z
When console logging: console.log(timestamp) // Mon Oct 15 2018 09:53:00 GMT+0200
I am using moment.js and already tried moment.utc() and moment(DATE).utc(). But it still adds the local time zone especially because I have to re-transform my moment objects back to the type Date with .toDate().
How can I resolve the time zone difference and get back a utc date to work with or the same structure as received?

try to format use as per desired.
let str = '2018-10-15T07:53:00.000Z';
let moment = moment(str).utcOffset(str)
console.log(moment.format('DD/MM/YYYY HH:mm'))
<script src="https://momentjs.com/downloads/moment.js"></script>
Second Snippet (to use the date object from string)
let str = '2018-10-15T07:53:00.000Z';
let moment = moment(str).utcOffset(str);
console.log(moment.toDate())
<script src="https://momentjs.com/downloads/moment.js"></script>

Your input is UTC and will be parsed just fine. Javascript Dates have no notion of timezone! The local timezone is applied by the static methods for serializing (Date.toString(), Date.toDateString() etc.) (Console.log(Date) uses Date.toString().)
Use Date.toLocaleString([],{timeZone:"UTC"}). Forcing UTC, you will see in the output the same time as the input. Much more details are here :-)
Here it is working:
console.log(new Date('2018-10-15T07:53:00.000Z').toLocaleString([],{timeZone:'UTC'}))

Converting moment UTC to Local date time

I put a UTC .NET/JSON date from .net on client side. When I run the following command:
moment(value.Planet.when).utc()
The returned date from webservice:
"/Date(1469271646000)/"
I get a date in the _d parameter showing the current accurate UTC date with GMT+0300 on right side.
I want to convert this time to local time on the user machine and what ever I do, I always get the time 3 hours back.
I do this:
moment(value.Planet.when).local().format('YYYY-MM-DD HH:mm:ss')
and I get the same date time as the UTC. I don't understand how can I get momentjs to show the UTC time relative to the local time. I checked that the momentjs object is indeed UTC.
I thought that if I pass the moment.utc() function the UTC date that I've got from the webservice (originally from the database), I can just run the local() function and I'll get the accurate hour relative to my area, but it didn't work.

You can use moment(date).format('YYYY-MM-DDTHH:mm:ss');
Eg:- if you date "/Date(1469271646000)/"
ip-> moment(1469271646000).format('YYYY-MM-DDTHH:mm:ss');
op-> "2016-07-23T16:30:46"

Do not use the _d property. It is for internal use only. See this answer, the user guide, or Maggie's blog post on the subject.
As far as you question of how to convert to local time, you don't actually need to convert at all. You're already parsing the input value in local mode, so you can just use it directly:
var m = moment("/Date(1469271646000)/"); // gives you a moment object in local mode.
var s = m.format(); // lets you format it as a string. Pass parameters if you like.
var d = m.toDate(); // gives you a Date object if you really need one
Try to avoid using Date objects unless they're required by some other controls or libraries you're using. Most operations can be done strictly on moment objects.

Convert string to new Date object in UTC timeZONE

Can anyone let me know how to convert a string to a date Object with UTC time zone in ExtJs?
String is "2015-10-07T23:59:00". I would like to get the same in Date Object without changing the timezone.

First of all, your date string does not have a timezone.
When you make a JavaScript date object from a string, there are two possible outcomes you could expect:
You may want the date to be 23:59 Local (23:59 CEST in my case).
In this case, you want to use new Date("2015-10-07 23:59:00") with plain javascript (note the missing T), or Ext.Date.parse("2015-10-07T23:59:00","c");.
You may want the date to be 23:59 UTC (e.g. 01:59 CEST).
In this case, you want to use new Date("2015-10-07T23:59:00").
Of course, whenever you output the date, you have to get the date in the correct time zone as well. The console/toString will usually show it in local time. JavaScript does provide getUTC... methods if you require other time zones.
You see, using Time Zones with JavaScript is a painful experience. I would recommend to try moment.js if you need full time zone support.

You can use Ext.Date.parse.It gives Date Object as output.It syntax is:
Ext.Date.parse( String input, String format, [Boolean strict] )
For Example:
Ext.Date.parse("2015-10-07T23:59:00", "Y-m-dTH:i:s");

try
var millisFromEpoch = Date.parse('2015-10-07T23:59:00');
it will parse date in GMT timezone, Ext.date.parse use the current timezone instead

Moment.js Convert Local time to UTC time does work

I would like to use Moment.js to convert a local time to UTC equivalent. I believe that I have the correct method in place, but it does not alter the time.
I'm in Sydney Australian +11 and expect the UTC time to be 11 hours earlier.
Internally on the moment object the isUTC flag changes from false to true, but the time does NOT shift, am I meant to use a different technique for this.
How do I actually get the current UTC date out of this object
Before Conversion
var val = '18/03/2015';
var selectedDate = moment(val, 'DD/MM/YYYY');
After Conversion
var a = selectedDate.utc()

I just tried this code and it seems like I get the correct UTC time. I guess I just want to confirm that what I am doing is correct way to access the UTC time from moment.js
a.format("YYYY-MM-DD HH:mm:ssZ")
I found that my usage pattern of in my application was incorrect
selectedDate.utc().format(fullFormat)
It should have been
moment.utc(selectedDate).format(fullFormat)

This works
moment(date_to_convert).utc().format("YYYY-MM-DD HH:mm:ss");

The question is old, but I also faced it. It may be useful to someone:
Using the method of utcOffset() to calculate the UTC time:
selectedDate = (moment(selectedDate).add(-(moment().utcOffset()), 'm'));
And explicitly specify UTC:
selectedDate = moment.parseZone(selectedDate).utc().format();

This is how you do it using moment-timezone
moment.tz(localDate, localTimeZone).utc()

This worked for me !!
selectedDate = moment(selectedDate).add(moment(selectedDate).utcOffset(), 'm').utc().format()

Create a local moment object from you local time and convert it to UTC then format it, then create a new UTC moment from that formatted UTC string
var localDateString = '24/04/2019';
var localDateStringFormat = 'DD/MM/YYYY';
var utcMoment = moment.utc(moment(localDateString, localDateStringFormat ).utc().format('YYYY-MM-DD HH:mm:ssZ'))
console.log(utcMoment);
<script src="https://momentjs.com/downloads/moment.js"></script>

After few frustrating hours, I found what was the problem
Short Answer: To convert time to utc, we need to use format()
Long Answer: Take the example
moment.utc(1559586600000).format('LLL')
.utc sets the isUTC flag to true.
When logging the date, the d key always shows the time in local timezone. (Which makes us believe its not working properly - as shown in your screenshot)
But we need to use .format to get the date/time in UTC format.
The above code returns June 3, 2019 6:30 PM which is the correct UTC time.

const moment = require('moment-timezone');
const dateTime='2020-12-21'
const timezone='America/Anchorage'
const dateTimeInUtc = moment(dateTime).tz(timezone).utc().format();
console.log('dateTimeInUtc',dateTimeInUtc);

const moment = require('moment-timezone');
const dateTime='2020-12-21'
const timezone='America/Anchorage'
const dateTimeInUtc = moment(dateTime).tz(timezone).utc().format();
console.log('dateTimeInUtc',dateTimeInUtc);

After few frustrating hours, I found what was the problem
Short Answer: To convert time to utc, we need to use format()
Long Answer: Take the example
moment.utc(1559586600000).format('LLL')
.utc sets the isUTC flag to true.
When logging the date, the d key always shows the time in local timezone. (Which makes us believe its not working properly - as shown in your screenshot)
But we need to use .format to get the date/time in UTC format.
The above code returns June 3, 2019 6:30 PM which is the correct UTC time.

Format date in a specific timezone

I'm using Moment.js to parse and format dates in my web app. As part of a JSON object, my backend server sends dates as a number of milliseconds from the UTC epoch (Unix offset).
Parsing dates in a specific timezone is easy -- just append the RFC 822 timezone identifier to the end of the string before parsing:
// response varies according to your timezone
const m1 = moment('3/11/2012 13:00').utc().format("MM/DD HH:mm")
// problem solved, always "03/11 17:00"
const m2 = moment('3/11/2012 13:00 -0400').utc().format("MM/DD HH:mm")
console.log({ m1, m2 })
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
But how do I format a date in a specifc timezone?
I want consistent results regardless of the browser's current time, but I don't want to display dates in UTC.

As pointed out in Manto's answer, .utcOffset() is the preferred method as of Moment 2.9.0. This function uses the real offset from UTC, not the reverse offset (e.g., -240 for New York during DST). Offset strings like "+0400" work the same as before:
// always "2013-05-23 00:55"
moment(1369266934311).utcOffset(60).format('YYYY-MM-DD HH:mm')
moment(1369266934311).utcOffset('+0100').format('YYYY-MM-DD HH:mm')
The older .zone() as a setter was deprecated in Moment.js 2.9.0. It accepted a string containing a timezone identifier (e.g., "-0400" or "-04:00" for -4 hours) or a number representing minutes behind UTC (e.g., 240 for New York during DST).
// always "2013-05-23 00:55"
moment(1369266934311).zone(-60).format('YYYY-MM-DD HH:mm')
moment(1369266934311).zone('+0100').format('YYYY-MM-DD HH:mm')
To work with named timezones instead of numeric offsets, include Moment Timezone and use .tz() instead:
// determines the correct offset for America/Phoenix at the given moment
// always "2013-05-22 16:55"
moment(1369266934311).tz('America/Phoenix').format('YYYY-MM-DD HH:mm')

A couple of answers already mention that moment-timezone is the way to go with named timezone. I just want to clarify something about this library that was pretty confusing to me. There is a difference between these two statements:
moment.tz(date, format, timezone)
moment(date, format).tz(timezone)
Assuming that a timezone is not specified in the date passed in:
The first code takes in the date and assumes the timezone is the one passed in.
The second one will take date, assume the timezone from the browser and then change the time and timezone according to the timezone passed in.
Example:
moment.tz('2018-07-17 19:00:00', 'YYYY-MM-DD HH:mm:ss', 'UTC').format() // "2018-07-17T19:00:00Z"
moment('2018-07-17 19:00:00', 'YYYY-MM-DD HH:mm:ss').tz('UTC').format() // "2018-07-18T00:00:00Z"
My timezone is +5 from utc. So in the first case it does not change and it sets the date and time to have utc timezone.
In the second case, it assumes the date passed in is in -5, then turns it into UTC, and that's why it spits out the date "2018-07-18T00:00:00Z"
NOTE: The format parameter is really important. If omitted moment might fall back to the Date class which can unpredictable behaviors
Assuming the timezone is specified in the date passed in:
In this case they both behave equally
Even though now I understand why it works that way, I thought this was a pretty confusing feature and worth explaining.

Use moment-timezone
moment(date).tz('Europe/Berlin').format(format)
Before being able to access a particular timezone, you will need to load it like so (or using alternative methods described here)
moment.tz.add('Europe/Berlin|CET CEST CEMT|-10 -20 -30')

.zone() has been deprecated, and you should use utcOffset instead:
// for a timezone that is +7 UTC hours
moment(1369266934311).utcOffset(420).format('YYYY-MM-DD HH:mm')

I was having the same issue with Moment.js. I've installed moment-timezone, but the issue wasn't resolved. Then, I did just what here it's exposed, set the timezone and it works like a charm:
moment(new Date({your_date})).zone("+08:00")
Thanks a lot!

Just came acreoss this, and since I had the same issue, I'd just post the results I came up with
when parsing, you could update the offset (ie I am parsing a data (1.1.2014) and I only want the date, 1st Jan 2014. On GMT+1 I'd get 31.12.2013. So I offset the value first.
moment(moment.utc('1.1.2014').format());
Well, came in handy for me to support across timezones
B

If you pass the timestamp as the parameter to moment() (e.g if the timezone is Asia/Hong_kong which is +08:00), what I do is:
const localDateTime = moment((item.createdAt.seconds + 8 * 3600) * 1000).format('YYYY-MM-DD HH:mm:ss');

You can Try this ,
Here you can get the date based on the Client Timezone (Browser).
moment(new Date().getTime()).zone(new Date().toString().match(/([-\+][0-9]+)\s/)[1]).format('YYYY-MM-DD HH:mm:ss')
The regex basically gets you the offset value.
Cheers!!