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How to convert utc timestamp to current time of another city?

I got timestamp utc of new york from weather api, want to display current time in New York but it gives output something like this 'UTC Sun Dec 01 2019 05:00:00 GMT+0530 (India Standard Time)'.
See the code for reference
// Code 1
//I get timestamp_utc when console.log(data)
//timestamp_utc: "2019-12-01T05:00:00"
const utc = new Date(data.timestamp_utc)
console.log('UTC', utc)
// UTC Sun Dec 01 2019 05:00:00 GMT+0530 (India Standard Time)
// Code 2
// Another code for getting current time but, failed
var usaTime = new Date().toLocaleString("en-US", {timeZone: timezone}); // Here timezone is from props
console.log('USA time: '+usaTime) // USA time: 12/1/2019, 4:59:58 AM
I also have timezone data getting from weather API. My aim is to get current time based on timezone or utc timestamp. As you can see both my trials are unsuccessful. Expected output is 6:39 PM which is now current time in New York. Is there any good solution?

Let me start with your 'code 2'. This is the same as what you wrote but with the timezone filled in...
const timezone = "America/New_York";
const usaTime = new Date().toLocaleString( "en-US", { timeZone: timezone});
console.log( 'usaTime =', usaTime );
For me this works. I get the current time in NY formatted correctly for USA. I'm not sure why yours did not work but I wonder what you specified for the timezone string.
I also a bit puzzled by your 'Code 1'. The 'new Date()' that you created is being converted to a string and then printed by your console.log statement, but this should result in a ISO 8601 string and you seem to be getting a locale string (the date format).

Though the example string you gave is in ISO 8601 format, it is not explicitly UTC because it does not end with a Z, nor does it end with a time zone offset such as +00:00. Thus when you parse it with the Date constructor, it is interpreted as local time. You can fix this by adding the Z yourself (assuming the timestamp_utc field is consistently a string in that format):
// timestamp_utc: "2019-12-01T05:00:00"
const utc = new Date(data.timestamp_utc + 'Z'); // adding the Z forces parsing as UTC
Now you have a Date object. However, if you just pass it to console.log, the output you see is implementation dependent. You will either see the local time in the same format you'd get by calling toString, or you will see the UTC time in the same format you'd get by calling toISOString.
To get the time in a different time zone, now you can call toLocaleString and pass the timeZone option. This assumes that the time zone is a valid IANA time zone identifier, and that the environment where the code is running fully supports the time zone features of the ECMAScript Internationalization Specification (ECMA-402). This is indeed the case with most modern browsers, but you will not get correct output in older browsers such as Internet Explorer.
const usEasternTime = utc.toLocaleString("en-US", {timeZone: 'America/New_York'});
Lastly from your variable name usaTime, I think perhaps you might be under the assumption that the US has a single time zone, but it does not. You will need to pass the correct time zone identifier. See the list on Wikipedia.

Define the time zones of origin ($ sourceDate) and destination (to convert).
$sourceTimeZone = 'utc';
$targetTimeZone = 'America/Bogota';
Separate the components of the date of origin that is in the format ‘m / d / y h: m: s’.
list($month, $day, $year, $hours, $minutes, $seconds) = sscanf($sourceDate, "%d/%d/%d %d:%d:%f");
Build the DateTime object indicating the date and time zone in which it is located.
$datetime = new DateTime("{$year}-{$month}-{$day} {$hours}:{$minutes}:{$seconds}",
new DateTimeZone($sourceTimeZone));
Modify the time zone of the DateTime to the destination time zone.
$datetime -> setTimezone(new DateTimeZone($targetTimeZone));
Get the components of the new date with the modified time zone.
list($month2, $day2, $year2, $hours2, $minutes2, $seconds2) = sscanf($datetime -> format(‘m/d/Y H:i:s’), “%d/%d/%d %d:%d:%f”);
Show the dates.
echo "En {$sourceTimeZone}: {$day}/{$month}/{$year} {$hours}:{$minutes}:{$seconds}<br/>";
echo "En {$targetTimeZone}: {$day2}/{$month2}/{$year2} {$hours2}:{$minutes2}:{$seconds2}<br/>";
PD: For JavaScript this can help you Convert time to different timezone with jQuery

angular $http.post changing date to UTC date

I was trying to post some data to my REST api which has date.
Now while I debug, my date parameter is a JS Date object with correct date in my timezone: Tue Apr 04 2017 00:00:00 GMT+0530
after it leaves my code, and I see the same in network tab, it is converted to UTC date: "2017-04-03T18:30:00.000Z"
I searched for the solution according to which I need to include locale file of angular in my index.html which I did:
<script type="text/javascript" src="resources/js/angular/angular-locale_en-in.js"></script>
but it doesn't help.
I've seen solutions like adding date format to filter or something, but I want a global solution.
Any help?
Thanks :)

Handling date, time, and timezone have confused me too. May be this answer gives you some insight on how you can handle them.
Try the following code in Chrome's developer console and see how same date is presented in different formats:
var date = new Date();
date.toISOString(); // "2017-04-29T09:54:28.714Z"
date.toGMTString(); //"Sat, 29 Apr 2017 09:54:28 GMT"
date.toLocalString(); //"4/29/2017, 3:24:28 PM"
Any date that you create on client always records the date at zero timezone offset i.e. UTC+/-00:00 Z. For simplicity you may think UTC and GMT as same. When it comes to display purpose the same date is presented as per the browser's timezone. If you do console.log (date) it'll output Sat Apr 29 2017 15:24:28 GMT+0530 (IST) but that doesn't mean that the internal recording of the date is as per browser's timezone. It's just presented on screen/console as per browser's timezone.
Look at date representations not as being converted from one timezone to another but look at them as different representation of the same date. In your browser it is represented as GMT+0530 offset and when it is sent to server it is the same date at zero timezone offset.
As per your comment, if you choose 4th Apr at 00:00 AM in GMT+0530 timezone, internally it'll be 3rd Apr at 18:30 PM in at GMT+0 i.e. zero timezone offset. Let it go to server as it is. When you need to use this date, it comes back from server as 3rd Apr and it'll be displayed in browser as per the browser's timezone offset. There is no conversion involved, it is one date with different representation.
I once asked a related question, may be this adds more clarification.
And overall, this answer is still same as #geminiousgoel and #charlietfl answers.

Scenario :
Send date from UI into API call as an epoch time (UNIX Time) instead of date string. You can use getTime() method to convert the date into epoch time.
var dateStr = "Tue Apr 04 2017 00:00:00 GMT+0530";
var dateEpoch = new Date(dateStr).getTime();
console.log(dateEpoch); // 1491244200000 (Local Time)
At receiver end, they have to convert this epoch time (UNIX time) into Date again.It will give the same local date\time that pass from the UI.
Sample screenshot

Like charlietfl suggested, probably the global hack would be to override Date.prototype.toJSON() method, but that's not a good practice.
Where are you using your $http.post call? The best place to submit an $http request would be in a service. If you use a service, then I suggest you to enwrap your public service API, so that you could have "public" and "private" methods: these could be utilities to perform common operations, such as data transformations, validations..
angular.service('bookStoreService', ['$http'], function($http) {
var normalizeBooks = function(booksArray){
booksArray.forEach(function(book){
// do something on the book
});
};
var updateBooks = function(books){
normalizeBooks(books);
$http.post('myurl', books);
};
return {
updateBooks : updateBooks
};
});

Passing UTC date to server is desired behavior. The client APIs are supposed to handle UTC time instead of assuming the dates are all local dates.
But anyways, you can convert the date to string based on local time zone, and pass the string to server.

i think you just can pass it as string (if the api you use accept strings) with the format you need, let say "Tue Apr 04 2017 00:00:00 GMT+0530" and save it in back-end as string and then when you retrieve it, it will be string and so it will not be changed in any way.

Jindal saab, It will work like this. When we select any date with date picker or just pass any value it takes the original local date but when we pass that value further it converts it into UTC, thereafter it needs to convert to local zone again at receiving end. Database saves date-time in UTC format.

Did you added the angular-locale_en-in.js library to your app? Something like this....
angular.module('myAngularApp', [
'ngLocale'])
Otherwise, the js library won't have any effect in your angular application.

Append UTC at the end so that Browser converts it into UTC date
var dateToServer =new Date(dateFromUser+" UTC");
now the dateToServer will be UTC DateTime format.

Json serializer parse date from string. On a client the date properties are stored as local date in browser time zone. When you are posting your object to server all date properties converts to utc string. In most cases it is a properly behavor. But sometimes you need set and send date in a server time zone. Often it is need when you should set only date whitout time. In that case you should define string propertie and set it manualy. I usaly apply this trick.
class Obj{
d: Date
}
class ObjDto{
constructor(obj: Obj){
this.d= dateTimeToIsoLocalDateString(obj.d)
}
d: string
}
...
export function DateTimeToDate(date) {
return new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
}
export function dateTimeToIsoLocalDateString(dateTime: Date): string {
if (dateTime === null) {
return null;
}
let date = DateTimeToDate(dateTime);
let res = date.toISOString().replace("Z", "");
return res;
}
For more understanding this theme you may learn this topic

//in res data of rest service in x the value is date in y value of y-axis
for (const i in res) {
console.log(i);
const a = {x: new Date(this.mimikatzlog[i].x), y: this.mimikatzlog[i].y};
this.policies.push(a);

Retrieving the timezone offset that was already input

I create a date like this:
var date = new Date('Wed, 19 Mar 2014 18:17:00 +0200');
This resolves to:
Wed Mar 19 2014 17:17:00 GMT+0100 (Central European Standard Time)
Is there a way to retrieve the "+0200" portion from the date object once it is created? I am trying to get this without parsing the input string and without the use of external libraries.
EDIT:
When I use
date.getTimezoneOffset();
It returns "-60", which corresponds to the local timezone offset, which in my case is GMT+0100. The question I am asking is whether the "+0200" from the input is lost in the Date object upon creation, or is it stored somewhere?

You can retrieve the timezoneoffset with date.getTimezoneOffset(); and use that to calculate it

From the Mozilla MSDN
The getTimezoneOffset() method returns the time-zone offset from UTC, in minutes, for the current locale.
date.getTimezoneOffset()
The time-zone offset is the difference, in minutes, between UTC and local time. Note that this means that the offset is positive if the local timezone is behind UTC and negative if it is ahead. For example, if your time zone is UTC+10 (Australian Eastern Standard Time), -600 will be returned. Daylight saving time prevents this value from being a constant even for a given locale.
A date object is stored as the number of milliseconds since the Unix epoch. So your input string is parsed and stored as a primitive number. So no, you can't retrieve aspects of your original input after it has been converted to a date object.

moment.js - UTC gives wrong date

Why does moment.js UTC always show the wrong date. For example from chrome's developer console:
moment(('07-18-2013')).utc().format("YYYY-MM-DD").toString()
// or
moment.utc(new Date('07-18-2013')).format("YYYY-MM-DD").toString()
Both of them will return "2013-07-17" why is it returning 17th instead of 18th, that was passed in.
But if I use momentjs without the utc:
moment(new Date('07-18-2013')).format("YYYY-MM-DD").toString()
I get back "2013-07-18" which is what I also expect when using moment.js UTC.
Does this mean we cannot get the correct date when using moment.js UTC?

By default, MomentJS parses in local time. If only a date string (with no time) is provided, the time defaults to midnight.
In your code, you create a local date and then convert it to the UTC timezone (in fact, it makes the moment instance switch to UTC mode), so when it is formatted, it is shifted (depending on your local time) forward or backwards.
If the local timezone is UTC+N (N being a positive number), and you parse a date-only string, you will get the previous date.
Here are some examples to illustrate it (my local time offset is UTC+3 during DST):
>>> moment('07-18-2013', 'MM-DD-YYYY').utc().format("YYYY-MM-DD HH:mm")
"2013-07-17 21:00"
>>> moment('07-18-2013 12:00', 'MM-DD-YYYY HH:mm').utc().format("YYYY-MM-DD HH:mm")
"2013-07-18 09:00"
>>> Date()
"Thu Jul 25 2013 14:28:45 GMT+0300 (Jerusalem Daylight Time)"
If you want the date-time string interpreted as UTC, you should be explicit about it:
>>> moment(new Date('07-18-2013 UTC')).utc().format("YYYY-MM-DD HH:mm")
"2013-07-18 00:00"
or, as Matt Johnson mentions in his answer, you can (and probably should) parse it as a UTC date in the first place using moment.utc() and include the format string as a second argument to prevent ambiguity.
>>> moment.utc('07-18-2013', 'MM-DD-YYYY').format("YYYY-MM-DD HH:mm")
"2013-07-18 00:00"
To go the other way around and convert a UTC date to a local date, you can use the local() method, as follows:
>>> moment.utc('07-18-2013', 'MM-DD-YYYY').local().format("YYYY-MM-DD HH:mm")
"2013-07-18 03:00"

Both Date and moment will parse the input string in the local time zone of the browser by default. However Date is sometimes inconsistent with this regard. If the string is specifically YYYY-MM-DD, using hyphens, or if it is YYYY-MM-DD HH:mm:ss, it will interpret it as local time. Unlike Date, moment will always be consistent about how it parses.
The correct way to parse an input moment as UTC in the format you provided would be like this:
moment.utc('07-18-2013', 'MM-DD-YYYY')
Refer to this documentation.
If you want to then format it differently for output, you would do this:
moment.utc('07-18-2013', 'MM-DD-YYYY').format('YYYY-MM-DD')
You do not need to call toString explicitly.
Note that it is very important to provide the input format. Without it, a date like 01-04-2013 might get processed as either Jan 4th or Apr 1st, depending on the culture settings of the browser.

use this :
return moment.utc(new Date(oData.CreatedAtUtc), 'MM/DD/YYYY h:mm A').local().format("YYYY-MM-DD HH:mm") + ' (' + timezoneAbbr + ')';

What format is this timestamp, and how can I format it in its own time

I have a problem converting a timestamp in javascript.
I have this timestamp:
2011-10-26T12:00:00-04:00
I have been trying to format it to be readable. So far, it converts this using the local time of my system instead of the GMT offset in the timestamp. I know the timezone that this was created in is EST. I'm in PST, so the times are being offset by 3 hours.
Instead of this showing as:
Wednesday October 26, 2011 12:00 pm
It shows as:
Wednesday October 26, 2011 9:00 am
I have tried a few different solutions, but the latest one is found here: http://blog.stevenlevithan.com/archives/date-time-format
I am less concerned with the formatting part as I am with figuring out how to handle the GMT offsets. Would appreciate any help and insight anyone can provide.

Date objects are created in the local zone. If the date string was created in a different time zone, then you need to adjust the date object to allow for the difference.
The abbreviations PST and EST are ambiguous on the web, there is no standard for time zone abbreviations and some represent two or zones. You should express your zone only in terms of +/- UTC or GMT (which are the same thing, more or less).
You can get the local time zone offset using Date.prototype.getTimezoneOffset, which returns the offset in minutes that must be added to a local time to get UTC. Calculate the offset for where the time string was created and apply it to the created date object (simply add or subtract the difference in minutes as appropriate).
If your time zone is -3hrs, getTimezoneOffset will return +180 for a date object created in that zone. If the string is from a zone -4hrs, its offset is +240. So you can do:
var localDate = new Date('2011-10-26T12:00:00') // date from string;
var originOffset = 240;
var localOffset = localDate.getTimezoneOffset();
localDate.setMinutes( localDate.getMinutes() + originOffset - localOffset );
Adding the origin offset sets it to UTC, subracting the local offset sets it to local time.
It would be much easier if the time string that was sent by the server was in UTC, that way you just apply the local offset.
Edit
IE will not parse a time string with an offset, and Chrome thinks that the above time string is UTC and adjusts for local offset. So don't let Date parse the string, do it manually.

It doesn't matter what time zone you are- the time stamp will result in a different local time for every different time-zone, but they all will be correct, and anyone checking the UTC time of the date will get the same time-stamp:
new Date('2011-10-26T12:00:00-04:00').toUTCString()
returns
Wed, 26 Oct 2011 16:00:00 GMT
and getTime() anywhere returns the same milliseconds universal timestamp:1319644800000