[javascript] Convert date to another timezone in JavaScript

I am looking for a function to convert date in one timezone to another.

It need two parameters,

• date (in format "2012/04/10 10:10:30 +0000")
• timezone string ("Asia/Jakarta")

The timezone string is described in http://en.wikipedia.org/wiki/Zone.tab

Is there an easy way to do this?

Stolen shamelessly from: http://www.techrepublic.com/article/convert-the-local-time-to-another-time-zone-with-this-javascript/6016329

/** 
 * function to calculate local time
 * in a different city
 * given the city's UTC offset
 */
function calcTime(city, offset) {

    // create Date object for current location
    var d = new Date();
   
    // get UTC time in msec
    var utc = d.getTime();
   
    // create new Date object for different city
    // using supplied offset
    var nd = new Date(utc + (3600000*offset));
   
    // return time as a string
    return "The local time in " + city + " is " + nd.toLocaleString();
}

this function is useful to calculate time zone value by providing name of a city/country and offset value

Time Zone Offset for your current timezone

date +%s -d '1 Jan 1970'

For my GMT+10 timezone (Australia) it returned -36000

You can use to toLocaleString() method for setting the timezone.

new Date().toLocaleString('en-US', { timeZone: 'Indian/Christmas' })

For India you can use "Indian/Christmas" and the following are the various timeZones,

"Antarctica/Davis",
    "Asia/Bangkok",
    "Asia/Hovd",
    "Asia/Jakarta",
    "Asia/Phnom_Penh",
    "Asia/Pontianak",
    "Asia/Saigon",
    "Asia/Vientiane",
    "Etc/GMT-7",
    "Indian/Christmas"

Okay, found it!

I'm using timezone-js. this is the code:

var dt = new timezoneJS.Date("2012/04/10 10:10:30 +0000", 'Europe/London');
dt.setTimezone("Asia/Jakarta");

console.debug(dt); //return formatted date-time in asia/jakarta

there is server issue pick gmt+0000 standard time zone you can change it by using library moment-timezone in javascript

const moment = require("moment-timezone")
const dateNew = new Date()
const changeZone = moment(dateNew);
changeZone.tz("Asia/Karachi").format("ha z");
// here you can paste "your time zone string"

Do it as easy:

const timeZone = Intl.DateTimeFormat().resolvedOptions().timeZone;
console.log(timeZone);

var d = new Date();
console.log(d.toLocaleString('en-US', { timeZone }));

Having looked around a lot including links from this page i found this great article, using moment timezone:

https://www.webniraj.com/2016/11/23/javascript-using-moment-js-to-display-dates-times-in-users-timezone/

To summarise it:

Get the user's timezone

var tz = moment.tz.guess();
console.info('Timezone: ' + tz);

Returns eg: Timezone: Europe/London

Set the default user timezone

moment.tz.setDefault(tz);

Set custom timezone

moment.tz.setDefault('America/Los_Angeles');

Convert date / time to local timezone, assumes original date/time is in UTC

moment.utc('2016-12-25 07:00').tz(tz).format('ddd, Do MMMM YYYY, h:mma');

Returns: Sun, 25th December 2016, 7:00am

Convert date/time to LA Time

moment.utc('2016-12-25 07:00').tz('America/Los_Angeles').format('ddd, Do MMMM YYYY, h:mma');

Returns: Sat, 24th December 2016, 11:00pm

Convert from LA time to London

moment.tz('2016-12-25 07:00', 'America/Los_Angeles').tz('Europe/London').format( 'ddd, Do MMMM YYYY, h:mma' );

Returns: Sun, 25th December 2016, 3:00pm

I recently did this in Typescript :

// fromTimezone example : Europe/Paris, toTimezone example: Europe/London
private calcTime( fromTimezone: string, toTimezone: string, dateFromTimezone: Date ): Date {
  const dateToGetOffset = new Date( 2018, 5, 1, 12 );

  const fromTimeString = dateToGetOffset.toLocaleTimeString( "en-UK", { timeZone: fromTimezone, hour12: false } );
  const toTimeString = dateToGetOffset.toLocaleTimeString( "en-UK", { timeZone: toTimezone, hour12: false } );

  const fromTimeHours: number = parseInt( fromTimeString.substr( 0, 2 ), 10 );
  const toTimeHours: number = parseInt( toTimeString.substr( 0, 2 ), 10 );

  const offset: number = fromTimeHours - toTimeHours;

  // convert to msec
  // add local time zone offset
  // get UTC time in msec
  const dateFromTimezoneUTC = Date.UTC( dateFromTimezone.getUTCFullYear(),
    dateFromTimezone.getUTCMonth(),
    dateFromTimezone.getUTCDate(),
    dateFromTimezone.getUTCHours(),
    dateFromTimezone.getUTCMinutes(),
    dateFromTimezone.getUTCSeconds(),
  );

  // create new Date object for different city
  // using supplied offset
  const dateUTC = new Date( dateFromTimezoneUTC + ( 3600000 * offset ) );

  // return time as a string
  return dateUTC;
}

I Use "en-UK" format because it is a simple one. Could have been "en-US" or whatever works.

If first argument is your locale timezone and seconde is your target timezone it returns a Date object with the correct offset.

there is an npm module called 'timezones.json' you can use for this; it basically consists of a json file with objects containing information on daylight savings and offset,....

for asia/jakarta it would be able to return this object:

{
  "value": "SE Asia Standard Time",
  "abbr": "SAST",
  "offset": 7,
  "isdst": false,
  "text": "(UTC+07:00) Bangkok, Hanoi, Jakarta",
  "utc": [
    "Antarctica/Davis",
    "Asia/Bangkok",
    "Asia/Hovd",
    "Asia/Jakarta",
    "Asia/Phnom_Penh",
    "Asia/Pontianak",
    "Asia/Saigon",
    "Asia/Vientiane",
    "Etc/GMT-7",
    "Indian/Christmas"
  ]
}

you can find it here:

https://github.com/dmfilipenko/timezones.json

https://www.npmjs.com/package/timezones.json

hope it's useful

Just set your desire country timezone and You can easily show in html it update using SetInteval() function after every one minut. function formatAMPM() manage 12 hour format and AM/PM time display.

$(document).ready(function(){
        var pakTime = new Date().toLocaleString("en-US", {timeZone: "Asia/Karachi"});
        pakTime = new Date(pakTime);

        var libyaTime = new Date().toLocaleString("en-US", {timeZone: "Africa/Tripoli"});
        libyaTime = new Date(libyaTime);



         document.getElementById("pak").innerHTML = "PAK  "+formatAMPM(pakTime);
         document.getElementById("ly").innerHTML = "LY   " +formatAMPM(libyaTime);

        setInterval(function(today) {
            var pakTime = new Date().toLocaleString("en-US", {timeZone: "Asia/Karachi"});
            pakTime = new Date(pakTime);

            var libyaTime = new Date().toLocaleString("en-US", {timeZone: "Africa/Tripoli"});
            libyaTime = new Date(libyaTime);


           document.getElementById("pak").innerHTML = "PAK  "+formatAMPM(pakTime);
           document.getElementById("ly").innerHTML = "LY  " +formatAMPM(libyaTime);

        },10000);

         function formatAMPM(date) {
            var hours = date.getHours();
            var minutes = date.getMinutes();
            var ampm = hours >= 12 ? 'pm' : 'am';
            hours = hours % 12;
            hours = hours ? hours : 12; // the hour '0' should be '12'
            minutes = minutes < 10 ? '0'+minutes : minutes;
            var strTime = hours + ':' + minutes + ' ' + ampm;
            return strTime;
        }


    });

You can try this also for convert date timezone to India:

var indianTimeZoneVal = new Date().toLocaleString('en-US', {timeZone: 'Asia/Kolkata'});
var indainDateObj = new Date(indianTimeZoneVal);
indainDateObj.setHours(indainDateObj.getHours() + 5);
indainDateObj.setMinutes(indainDateObj.getMinutes() + 30);
console.log(indainDateObj);

Got it !

Wanted to force the date shown = server date, no mattter the local settings (UTC).

My server is GMT-6 --> new Date().getTimezoneOffset() = 360.

myTZO = 360;
myNewDate=new Date(myOldDateObj.getTime() + (60000*(myOldDateObj.getTimezoneOffset()-myTZO)));
alert(myNewDate);

You can also use https://www.npmjs.com/package/ctoc_timezone

It has got much simple implementation and format customisation.

Changing format in toTimeZone:

CtoC.toTimeZone(new Date(),"EST","Do MMM YYYY hh:mm:ss #{EST}");

Output :

28th Feb 2013 19:00:00 EST

You can explore multiple functionalities in the doc.

If you just need to convert timezones I have uploaded a stripped-down version of moment-timezone with just the bare minimum functionallity. Its ~1KB + data:

S.loadData({
    "zones": [
        "Europe/Paris|CET CEST|-10 -20|01010101010101010101010|1GNB0 1qM0 11A0 1o00 11A0 1o00 11A0 1o00 11A0 1qM0 WM0 1qM0 WM0 1qM0 11A0 1o00 11A0 1o00 11A0 1qM0 WM0 1qM0|11e6",
        "Australia/Sydney|AEDT AEST|-b0 -a0|01010101010101010101010|1GQg0 1fA0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1fA0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0 1cM0|40e5",
    ],
    "links": [
        "Europe/Paris|Europe/Madrid",
    ]
});

let d = new Date();
console.log(S.tz(d, "Europe/Madrid").toLocaleString());
console.log(S.tz(d, "Australia/Sydney").toLocaleString());

I was having trouble using Moment Timezone. I am adding this answer just so if somebody else faces the same issue. So I have a date string 2018-06-14 13:51:00 coming from my API. I know that this is stored in UTC but the string doesn't speak for itself.

I let moment timezone know, what timezone this date is from by doing:

let uTCDatetime = momentTz.tz("2018-06-14 13:51:00", "UTC").format();
// If your datetime is from any other timezone then add that instead of "UTC"
// this actually makes the date as : 2018-06-14T13:51:00Z

Now I would like to convert it to a specific timezone by doing:

let dateInMyTimeZone = momentTz.tz(uTCDatetime, "Asia/Kolkata").format("YYYY-MM-DD HH:mm:ss");
// now this results into: 2018-06-14 19:21:00, which is the corresponding date in my timezone.

Set a variable with year, month, and day separated with '-' symbols, plus a 'T' and the time in HH:mm:ss pattern, followed by +01:00 at the end of the string (in my case the time zone is +1). Then use this string as the argument for the date constructor.

//desired format: 2001-02-04T08:16:32+01:00
dateAndTime = year+"-"+month+"-"+day+"T"+hour+":"+minutes+":00+01:00";

var date = new Date(dateAndTime );

Here is my code, it is working perfectly, you can try with give below demo:

$(document).ready(function() {_x000D_
   //EST_x000D_
setInterval( function() {_x000D_
var estTime = new Date();_x000D_
 var currentDateTimeCentralTimeZone = new Date(estTime.toLocaleString('en-US', { timeZone: 'America/Chicago' }));_x000D_
var seconds = currentDateTimeCentralTimeZone.getSeconds();_x000D_
var minutes = currentDateTimeCentralTimeZone.getMinutes();_x000D_
var hours =  currentDateTimeCentralTimeZone.getHours()+1;//new Date().getHours();_x000D_
 var am_pm = currentDateTimeCentralTimeZone.getHours() >= 12 ? "PM" : "AM";_x000D_
_x000D_
if (hours < 10){_x000D_
     hours = "0" + hours;_x000D_
}_x000D_
_x000D_
if (minutes < 10){_x000D_
     minutes = "0" + minutes;_x000D_
}_x000D_
if (seconds < 10){_x000D_
     seconds = "0" + seconds;_x000D_
}_x000D_
    var mid='PM';_x000D_
    if(hours==0){ //At 00 hours we need to show 12 am_x000D_
    hours=12;_x000D_
    }_x000D_
    else if(hours>12)_x000D_
    {_x000D_
    hours=hours%12;_x000D_
    mid='AM';_x000D_
    }_x000D_
    var x3 = hours+':'+minutes+':'+seconds +' '+am_pm_x000D_
// Add a leading zero to seconds value_x000D_
$("#sec").html(x3);_x000D_
},1000);_x000D_
_x000D_
_x000D_
});

<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
<p class="date_time"><strong id="sec"></strong></p>_x000D_
</body>_x000D_
</html>

People familiar with the java 8 java.time package, or joda-time will probably love the new kid on the block: the js-joda library.

Install

npm install js-joda js-joda-timezone --save

Example

<script src="node_modules/js-joda/dist/js-joda.js"></script>
<script src="node_modules/js-joda-timezone/dist/js-joda-timezone.js"></script>
<script>
var dateStr = '2012/04/10 10:10:30 +0000';
JSJoda.use(JSJodaTimezone);
var j = JSJoda;
// https://js-joda.github.io/js-joda/esdoc/class/src/format/DateTimeFormatter.js~DateTimeFormatter.html#static-method-of-pattern
var zonedDateTime = j.ZonedDateTime.parse(dateStr, j.DateTimeFormatter.ofPattern('yyyy/MM/dd HH:mm:ss xx'));
var adjustedZonedDateTime = zonedDateTime.withZoneSameInstant(j.ZoneId.of('America/New_York'));
console.log(zonedDateTime.toString(), '=>', adjustedZonedDateTime.toString());
// 2012-04-10T10:10:30Z => 2012-04-10T06:10:30-04:00[America/New_York]
</script>

In true java nature, it's pretty verbose lol. But, being a ported java library, especially considering they ported 1800'ish test cases, it also probably works superbly accurately.

Chrono manipulation is hard. That's why many other libraries are buggy in edge cases. Moment.js seems to get timezones right, but the other js libs I've seen, including timezone-js, don't seem trustworthy.

quick and dirty manual hour changer and return:

return new Date(new Date().setHours(new Date().getHours()+3)).getHours()

I don't know an easy method to convert a date object to any time zone, but if you want to convert it to the local time zone, you can just convert it with Date.prototype.getTime() to the corresponding number of milliseconds, and back again.

date = new Date('2016-05-24T13:07:20');
date = new Date(date.getTime());

For example, date.getHours() will now return 15 instead of 13 if you are, like me, in Austria (and it's summer).

I've read that the various datetime functions may exhibit non-standard behaviour in some browsers, so test this first. I can confirm that it works in Chrome.

For moment.js users, you can now use moment-timezone. Using it, your function would look something like this:

function toTimeZone(time, zone) {
    var format = 'YYYY/MM/DD HH:mm:ss ZZ';
    return moment(time, format).tz(zone).format(format);
}

Most browsers support the toLocaleString function with arguments, older browsers usually ignore the arguments.

const str = new Date().toLocaleString('en-US', { timeZone: 'Asia/Jakarta' });
console.log(str);

I should note that I am restricted with respect to which external libraries that I can use. moment.js and timezone-js were NOT an option for me.

The js date object that I have is in UTC. I needed to get the date AND time from this date in a specific timezone('America/Chicago' in my case).

 var currentUtcTime = new Date(); // This is in UTC

 // Converts the UTC time to a locale specific format, including adjusting for timezone.
 var currentDateTimeCentralTimeZone = new Date(currentUtcTime.toLocaleString('en-US', { timeZone: 'America/Chicago' }));

 console.log('currentUtcTime: ' + currentUtcTime.toLocaleDateString());
 console.log('currentUtcTime Hour: ' + currentUtcTime.getHours());
 console.log('currentUtcTime Minute: ' + currentUtcTime.getMinutes());
 console.log('currentDateTimeCentralTimeZone: ' +        currentDateTimeCentralTimeZone.toLocaleDateString());
 console.log('currentDateTimeCentralTimeZone Hour: ' + currentDateTimeCentralTimeZone.getHours());
 console.log('currentDateTimeCentralTimeZone Minute: ' + currentDateTimeCentralTimeZone.getMinutes());

UTC is currently 6 hours ahead of 'America/Chicago'. Output is:

currentUtcTime: 11/25/2016
currentUtcTime Hour: 16
currentUtcTime Minute: 15

currentDateTimeCentralTimeZone: 11/25/2016
currentDateTimeCentralTimeZone Hour: 10
currentDateTimeCentralTimeZone Minute: 15

If you don't want to import some big library you could just use Intl.DateTimeFormat to convert Date objects to different timezones.

// Specifying timeZone is what causes the conversion, the rest is just formatting
const options = {
  year: '2-digit', month: '2-digit', day: '2-digit',
  hour: '2-digit', minute: '2-digit', second: '2-digit',
  timeZone: 'Asia/Jakarta',
  timeZoneName: 'short'
}
const formatter = new Intl.DateTimeFormat('sv-SE', options)
const startingDate = new Date("2012/04/10 10:10:30 +0000")

const dateInNewTimezone = formatter.format(startingDate) 
console.log(dateInNewTimezone) // 12-04-10 17:10:30 GMT+7

Offsets, daylight saving, and changes in the past will be taken care of for you.

Provide the desired time zone, for example "Asia/Tehran" to change the current time to that timezone. I used "Asia/Seoul".

You can use the following codes. change the style if you need to do so.

please keep in mind that if you want to have h:m:s format instead of HH:MM:SS, you'll have to remove "function kcwcheckT(i)".

function kcwcheckT(i) {
  if (i < 10) {
    i = "0" + i;
  }
  return i;
}
function kcwt() {
var d = new Date().toLocaleString("en-US", {timeZone: "Asia/Seoul"});
d = new Date(d);
  var h = d.getHours();
  var m = d.getMinutes();
  var s = d.getSeconds();
  h = kcwcheckT(h);
  m = kcwcheckT(m);
  s = kcwcheckT(s);
  document.getElementById("kcwcurtime").innerHTML = h + ":" + m + ":" + s;
  var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];
document.getElementById("kcwcurday").innerHTML = days[d.getDay()]
}
kcwt();
window.setInterval(kcwt, 1000);

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