javascripttimezonedate-formattingecmascript-temporal

Reputation: 19071

How to ISO 8601 format a Date with Timezone Offset in JavaScript?

Goal: Find the local time and UTC time offset then construct the URL in following format.

Example URL: /Actions/Sleep?duration=2002-10-10T12:00:00−05:00

The format is based on the W3C recommendation. The documentation says:

For example, 2002-10-10T12:00:00−05:00 (noon on 10 October 2002, Central Daylight Savings Time as well as Eastern Standard Time in the U.S.) is equal to 2002-10-10T17:00:00Z, five hours later than 2002-10-10T12:00:00Z.

So based on my understanding, I need to find my local time by new Date() then use getTimezoneOffset() function to compute the difference then attach it to the end of string.

Get local time with format

var local = new Date().format("yyyy-MM-ddThh:mm:ss"); // 2013-07-02T09:00:00

Get UTC time offset by hour

var offset = local.getTimezoneOffset() / 60; // 7

Construct URL (time part only)

var duration = local + "-" + offset + ":00"; // 2013-07-02T09:00:00-7:00

The above output means my local time is 2013/07/02 9am and difference from UTC is 7 hours (UTC is 7 hours ahead of local time)

So far it seems to work but what if getTimezoneOffset() returns negative value like -120?

I'm wondering how the format should look like in such case because I cannot figure out from W3C documentation.

Upvotes: 236

Answers (25)

Andre Angeloni

Reputation: 122

I used formatISO from date-fns to resolve this.

import { formatISO } from 'date-fns'

const localDate = formatISO(new Date())

console.log(localDate)

// 2024-07-28T18:37:22-03:00

Upvotes: 0

radio_electronics

Reputation: 33

var my_iso_date = new Date(Date.parse(Date()) - new Date().getTimezoneOffset()*60*1000)

This object outputs (in node repl) for example (ISO format AND correct timezone):

2024-07-06T11:34:37.000Z

And then you can use the slice() function to just get the date if you need that.

my_iso_date.toISOString().slice(0,10)

this outputs:

'2024-07-06'

Upvotes: 0

Prhyme

Reputation: 131

This would do

new Date().toLocaleString('sv',{timeZoneName:"longOffset"}).replace(' ','T').replace(' GMT','')

will give out something like 2024-06-20T13:33:22+05:30

Upvotes: 1

Adán Escobar

Reputation: 4573

a simple way to get:

//using a sample date
let iso_str = '2022-06-11T01:51:59.618Z';
let d = new Date(iso_str);

let tz = 'America/Santiago'
let options = {
    timeZone:tz ,
    timeZoneName:'longOffset',
    year: 'numeric',
    month: 'numeric',
    day: 'numeric',
    hour: 'numeric',
    minute: 'numeric',
    second: 'numeric',
    fractionalSecondDigits: 3
}


str_locale = d.toLocaleString("sv-SE",options);
iso_str_tz = str_locale
             .replace(/(\d{4})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2}):(\d{2}),(\d+)\s+/,'$1-$2-$3T$4:$5:$6.$7')
             .replace('GMT−', '-' )
             .replace('GMT+','+')


console.log('iso_str               : ',iso_str);
console.log('str_locale            : ',str_locale);
console.log('iso_str_tz            : ',iso_str_tz);
console.log('iso_str_tz --> date   : ',new Date(iso_str_tz));
console.log('iso_str_tz --> iso_str: ',new Date(iso_str_tz).toISOString());

Upvotes: 1

Jonathan Steele

Reputation: 707

My answer is a slight variation for those who just want today's date in the local timezone in the YYYY-MM-DD format.

Let me be clear:

My Goal: get today's date in the user's timezone but formatted as ISO8601 (YYYY-MM-DD)

Here is the code:

new Date().toLocaleDateString("sv") // "2020-02-23" //

This works because the Swedish language locale (svenska) uses the ISO 8601 format.

Upvotes: 36

Bishop

Reputation: 131

If you are looking for an easy one-liner to get the current date in ISO format here it is.

const currentIsoDateString = new Date(Date.now() - new Date().getTimezoneOffset() * 60000).toISOString()

You can change this to get the ISO date/time string for other dates by replacing the Date.now() with your epoch date integer.

Here is how it works from the inside out. Date.now() returns the current time in milliseconds since the epoch Jan. 1st 1970. For me the current local date/time is 2023-07-05 09:57:32 (ex. 1688565167374) but Date.now does not care about the local time, it just gives the time from the epoch regardless of local time, so we need to adjust.

new Date().getTimezonOffset() returns the local timezone offset from UTC. In my case it is 240 or 4 hours. We multiply these minutes by 60000 to convert it to milliseconds and subtract the result from the UTC.

Then we can use the handy .toISOString() native function to get a nicely formatted ISO string. '2023-07-05T09:58:18.119Z'

No libraries required :-)

Upvotes: 10

Gayan Kalhara

Reputation: 755

Here's another way a convert your date with an offset.

function toCustomDateString(date, offset) {
  function pad(number) {
    if (number < 10) {
      return "0" + number;
    }
    return number;
  }

  var offsetHours = offset / 60;
  var offsetMinutes = offset % 60;

  var sign = (offset > 0) ? "+" : "-";
  offsetHours = pad(Math.floor(Math.abs(offsetHours)));
  offsetMinutes = pad(Math.abs(offsetMinutes));

  return date.getFullYear() +
    "-" + pad(date.getMonth() + 1) +
    "-" + pad(date.getDate()) +
    "T" + pad(date.getHours()) +
    ":" + pad(date.getMinutes()) +
    ":" + pad(date.getSeconds()) +
    sign + offsetHours +
    ":" + offsetMinutes;
}

Then you can use it like this:

var date = new Date();
var offset = 330; // offset in minutes from UTC, for India it is 330 minutes ahead of UTC
var customDateString = toCustomDateString(date, offset);
console.log(customDateString);
// Output: "2023-02-09T10:29:31+05:30"

Upvotes: 0

Codeinator

Reputation: 719

I found another more easy solution:

let now = new Date();
// correct time zone offset for generating iso string
now.setMinutes(now.getMinutes() - now.getTimezoneOffset())
now = now.toISOString();

I undo the timezone offset by substracting it from the current date object. The UTC time from the date object is now pointing to the local time. That gives you the possibility to get the iso date for the local time.

Upvotes: -1

ino

Reputation: 1125

Alternative approach with dayjs

import dayjs from "dayjs"

const formattedDateTime = dayjs(new Date()).format()

console.log(formattedDateTime) // Prints 2022-11-09T07:49:29+03:00

Upvotes: 0

Omer Gurarslan

Reputation: 1027

Using moment.js, you can use keepOffset parameter of toISOString:

toISOString(keepOffset?: boolean): string;

moment().toISOString(true)

Upvotes: 0

sffc

Reputation: 6414

Use Temporal.

Temporal.Now.zonedDateTimeISO().toString()
// '2022-08-09T14:16:47.762797591-07:00[America/Los_Angeles]'

To omit the fractional seconds and IANA time zone:

Temporal.Now.zonedDateTimeISO().toString({
  timeZoneName: "never",
  fractionalSecondDigits: 0
})
// '2022-08-09T14:18:34-07:00'

Note: Temporal is currently (2022) available as a polyfill, but will soon be available in major browsers.

Upvotes: 5

Wagner Pereira

Reputation: 1078

date to ISO string,
with local(computer) time zone,
with or without milliseconds

ISO ref: https://en.wikipedia.org/wiki/ISO_8601

how to use: toIsoLocalTime(new Date())

function toIsoLocalTime(value) {
    if (value instanceof Date === false)
        value = new Date();    
    const off = value.getTimezoneOffset() * -1;
    const del = value.getMilliseconds() ? 'Z' : '.'; // have milliseconds ?
    value = new Date(value.getTime() + off * 60000); // add or subtract time zone
    return value
        .toISOString()
        .split(del)[0]
        + (off < 0 ? '-' : '+')
        + ('0' + Math.abs(Math.floor(off / 60))).substr(-2)
        + ':'
        + ('0' + Math.abs(off % 60)).substr(-2);
}

function test(value) {
    const event = new Date(value);
    console.info(value + ' -> ' + toIsoLocalTime(event) + ', test = ' + (event.getTime() === (new Date(toIsoLocalTime(event))).getTime() ));
}

test('2017-06-14T10:00:00+03:00'); // test with timezone
test('2017-06-14T10:00:00'); // test with local timezone
test('2017-06-14T10:00:00Z'); // test with UTC format
test('2099-12-31T23:59:59.999Z'); // date with milliseconds
test((new Date()).toString()); // now

Upvotes: 4

Nelu

Reputation: 18680

With luxon:

DateTime.now().toISODate() // 2022-05-23

Upvotes: 0

Daniel Danielecki

Reputation: 10502

let myDate = new Date(dateToBeFormatted * 1000); // depends if you have milliseconds, or seconds, then the * 1000 might be not, or required.
timeOffset = myDate.getTimezoneOffset();
myDate = new Date(myDate.getTime() - (timeOffset * 60 * 1000));

console.log(myDate.toISOString().split('T')[0]);

Inspired by https://stackoverflow.com/a/29774197/11127383, including timezone offset comment.

Upvotes: 0

OhadR

Reputation: 8839

consider using moment (like Matt's answer).

From version 2.20.0, you may call .toISOString(true) to prevent UTC conversion:

console.log(moment().toISOString(true));

// sample output:   2022-04-06T16:26:36.758+03:00

Upvotes: 2

Steven Moseley

Reputation: 16325

Here's a simple helper function that will format JS dates for you.

function toIsoString(date) {
  var tzo = -date.getTimezoneOffset(),
      dif = tzo >= 0 ? '+' : '-',
      pad = function(num) {
          return (num < 10 ? '0' : '') + num;
      };

  return date.getFullYear() +
      '-' + pad(date.getMonth() + 1) +
      '-' + pad(date.getDate()) +
      'T' + pad(date.getHours()) +
      ':' + pad(date.getMinutes()) +
      ':' + pad(date.getSeconds()) +
      dif + pad(Math.floor(Math.abs(tzo) / 60)) +
      ':' + pad(Math.abs(tzo) % 60);
}

var dt = new Date();
console.log(toIsoString(dt));

Upvotes: 328

Arnold Gandarillas

Reputation: 4322

Just my two cents here

I was facing this issue with datetimes so what I did is this:

const moment = require('moment-timezone')

const date = moment.tz('America/Bogota').format()

Then save date to db to be able to compare it from some query.

To install moment-timezone

npm i moment-timezone

Upvotes: 3

Nahuel Greco

Reputation: 1249

Check this:

function dateToLocalISO(date) {
    const off    = date.getTimezoneOffset()
    const absoff = Math.abs(off)
    return (new Date(date.getTime() - off*60*1000).toISOString().substr(0,23) +
            (off > 0 ? '-' : '+') + 
            Math.floor(absoff / 60).toFixed(0).padStart(2,'0') + ':' + 
            (absoff % 60).toString().padStart(2,'0'))
}

// Test it:
d = new Date()

dateToLocalISO(d)
// ==> '2019-06-21T16:07:22.181-03:00'

// Is similar to:

moment = require('moment')
moment(d).format('YYYY-MM-DDTHH:mm:ss.SSSZ') 
// ==> '2019-06-21T16:07:22.181-03:00'

Upvotes: 12

Ranch Camal

Reputation: 570

function setDate(){
    var now = new Date();
    now.setMinutes(now.getMinutes() - now.getTimezoneOffset());
    var timeToSet = now.toISOString().slice(0,16);

    /*
        If you have an element called "eventDate" like the following:

        <input type="datetime-local" name="eventdate" id="eventdate" />

        and you would like to  set the current and minimum time then use the following:
    */

    var elem = document.getElementById("eventDate");
    elem.value = timeToSet;
    elem.min = timeToSet;
}

Upvotes: -1

Extragorey

Reputation: 1764

You can achieve this with a few simple extension methods. The following Date extension method returns just the timezone component in ISO format, then you can define another for the date/time part and combine them for a complete date-time-offset string.

Date.prototype.getISOTimezoneOffset = function () {
    const offset = this.getTimezoneOffset();
    return (offset < 0 ? "+" : "-") + Math.floor(Math.abs(offset / 60)).leftPad(2) + ":" + (Math.abs(offset % 60)).leftPad(2);
}

Date.prototype.toISOLocaleString = function () {
    return this.getFullYear() + "-" + (this.getMonth() + 1).leftPad(2) + "-" +
        this.getDate().leftPad(2) + "T" + this.getHours().leftPad(2) + ":" +
        this.getMinutes().leftPad(2) + ":" + this.getSeconds().leftPad(2) + "." +
        this.getMilliseconds().leftPad(3);
}

Number.prototype.leftPad = function (size) {
    var s = String(this);
    while (s.length < (size || 2)) {
        s = "0" + s;
    }
    return s;
}

Example usage:

var date = new Date();
console.log(date.toISOLocaleString() + date.getISOTimezoneOffset());
// Prints "2020-08-05T16:15:46.525+10:00"

I know it's 2020 and most people are probably using Moment.js by now, but a simple copy & pastable solution is still sometimes handy to have.

(The reason I split the date/time and offset methods is because I'm using an old Datejs library which already provides a flexible toString method with custom format specifiers, but just doesn't include the timezone offset. Hence, I added toISOLocaleString for anyone without said library.)

Upvotes: 7

gildniy

Reputation: 3903

Here are the functions I used for this end:

function localToGMTStingTime(localTime = null) {
    var date = localTime ? new Date(localTime) : new Date();
    return new Date(date.getTime() + (date.getTimezoneOffset() * 60000)).toISOString();
};

function GMTToLocalStingTime(GMTTime = null) {
    var date = GMTTime ? new Date(GMTTime) : new Date();;
    return new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString();
};

Upvotes: 1

Captain Fantastic

Reputation: 452

No moment.js needed: Here's a full round trip answer, from an input type of "datetime-local" which outputs an ISOLocal string to UTCseconds at GMT and back:

<input type="datetime-local" value="2020-02-16T19:30">

isoLocal="2020-02-16T19:30"
utcSeconds=new Date(isoLocal).getTime()/1000

//here you have 1581899400 for utcSeconds

let isoLocal=new Date(utcSeconds*1000-new Date().getTimezoneOffset()*60000).toISOString().substring(0,16)
2020-02-16T19:30

Upvotes: 3

Tom

Reputation: 17844

I think it is worth considering that you can get the requested info with just a single API call to the standard library...

new Date().toLocaleString( 'sv', { timeZoneName: 'short' } );

// produces "2019-10-30 15:33:47 GMT−4"

You would have to do text swapping if you want to add the 'T' delimiter, remove the 'GMT-', or append the ':00' to the end.

But then you can easily play with the other options if you want to eg. use 12h time or omit the seconds etc.

Note that I'm using Sweden as locale because it is one of the countries that uses ISO 8601 format. I think most of the ISO countries use this 'GMT-4' format for the timezone offset other then Canada which uses the time zone abbreviation eg. "EDT" for eastern-daylight-time.

You can get the same thing from the newer standard i18n function "Intl.DateTimeFormat()" but you have to tell it to include the time via the options or it will just give date.

Upvotes: 69

Bbb

Reputation: 649

This is my function for the clients timezone, it's lite weight and simple

  function getCurrentDateTimeMySql() {        
      var tzoffset = (new Date()).getTimezoneOffset() * 60000; //offset in milliseconds
      var localISOTime = (new Date(Date.now() - tzoffset)).toISOString().slice(0, 19).replace('T', ' ');
      var mySqlDT = localISOTime;
      return mySqlDT;
  }

Upvotes: 9

Matt Johnson-Pint

Reputation: 241420

getTimezoneOffset() returns the opposite sign of the format required by the spec that you referenced.

This format is also known as ISO8601, or more precisely as RFC3339.

In this format, UTC is represented with a Z while all other formats are represented by an offset from UTC. The meaning is the same as JavaScript's, but the order of subtraction is inverted, so the result carries the opposite sign.

Also, there is no method on the native Date object called format, so your function in #1 will fail unless you are using a library to achieve this. Refer to this documentation.

If you are seeking a library that can work with this format directly, I recommend trying moment.js. In fact, this is the default format, so you can simply do this:

var m = moment();    // get "now" as a moment
var s = m.format();  // the ISO format is the default so no parameters are needed

// sample output:   2013-07-01T17:55:13-07:00

This is a well-tested, cross-browser solution, and has many other useful features.

Upvotes: 84

How to ISO 8601 format a Date with Timezone Offset in JavaScript?

Answers (25)

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