Related
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.
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));
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.
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.
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 Sweden locale uses the ISO 8601 format.
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;
}
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'
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.)
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
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
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
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
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.
With luxon:
DateTime.now().toISODate() // 2022-05-23
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();
};
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.
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());
Using moment.js, you can use keepOffset parameter of toISOString:
toISOString(keepOffset?: boolean): string;
moment().toISOString(true)
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
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"
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;
}
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.
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.
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));
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.
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.
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 Sweden locale uses the ISO 8601 format.
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;
}
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'
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.)
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
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
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
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
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.
With luxon:
DateTime.now().toISODate() // 2022-05-23
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();
};
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.
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());
Using moment.js, you can use keepOffset parameter of toISOString:
toISOString(keepOffset?: boolean): string;
moment().toISOString(true)
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
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"
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;
}
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.
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.
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));
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.
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.
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 Sweden locale uses the ISO 8601 format.
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;
}
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'
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.)
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
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
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
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
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.
With luxon:
DateTime.now().toISODate() // 2022-05-23
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();
};
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.
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());
Using moment.js, you can use keepOffset parameter of toISOString:
toISOString(keepOffset?: boolean): string;
moment().toISOString(true)
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
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"
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;
}
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.
I try to write a function to convert date and time from string to date. Here's my code:
var date_one = '2015-08-12 14:15:00';
var date_two = '2015-08-13 15:00:00';
console.log(date_one); //2015-08-12 14:15:00
console.log(date_two); //2015-08-13 15:00:00
var timeStamp_date_one = new Date(date_one).getTime() ; //NAN?
console.log(typeof timeStamp_date_one);//number
var timeStamp_date_two = new Date(date_two).getTime() ;//NAN?
console.log(typeof timeStamp_date_two);//number
//since you are having both datetime in numer time
//you can compare then to any logical oparation ( >, < ,= ,!= ,== ,!== ,>= AND <=)
//to be able to work with this date and time agin you need to convert it to an object
var newTime = new Date(timeStamp_date_one) ;
console.log(typeof newTime) ;//object
// you can the use this following function to convert your date and time to any format you want
console.log(DateAndTimeFormat(newTime , 'time')) ;// NaN:NaN ???
console.log(DateAndTimeFormat(newTime , 'date_time')) ;// NaN/NaN/NaN NaN:NaN ???
function DateAndTimeFormat(dateAndTime, type) {
switch (type) {
case 'time':
return dateAndTime.getHours() + ':' + (dateAndTime.getMinutes() < 10 ? '0' : '') +
dateAndTime.getMinutes()
case 'date':
return dateAndTime.getMonth() + 1 + '/' + dateAndTime.getDate() + '/' +
dateAndTime.getFullYear()
case 'date_time':
return dateAndTime.getMonth() + 1 + '/' + dateAndTime.getDate() + '/' +
dateAndTime.getFullYear() + ' ' + dateAndTime.getHours() + ':' +
(dateAndTime.getMinutes() < 10 ? '0' : '') + dateAndTime.getMinutes()
}
}
Why in this case I talways take a "Not-a-Number" value ? I expect that Object could be transfered to Data object like in this code. Somebody can told my why and how can I repair that code? Thank's a lot
As specified by https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date, when working with years like you are doing, the format is not "YYYY-MM-DD HH:MM:SS" but "YYYY-MM-DDTHH:MM:SS" (Notice the 'T' instead of the space)
var date_one = '2015-08-12T14:15:00';
var date_two = '2015-08-13T15:00:00';
With these values, your code works.
This is relative to the ISO 8601 standard
I would recommend to parse and split into chunks the string representing the date first and then use new Date(year, month, day, hour, minutes, seconds, milliseconds); constructor to be 100% sure there are no any local date format issues.
What is the best way to convert the following string to a javascript date string format of MM/DD/YYYY?
"25-AUG-11"
The best way is that given by jmeans in the comment to the question.
When given a string representing a date in one format, then the "best way" to covert it to another format is to first parse it to a date, then format the date to the string you want.
Unless this is a one-time conversion, don't waste your time writing code to format and parse dates! This is a solved problem that is implemented by many thoroughly tested libraries. If you are doing anything that involves date handling and computation, doing things on your own can be error-prone.
One good lightweight date library is moment.js.
Include moment.js like this:
<script src="//cdnjs.cloudflare.com/ajax/libs/moment.js/2.0.0/moment.min.js"></script>
Then the JavaScript code for your particular example can be:
alert(moment("25-AUG-11", "DD-MMM-YY").format("MM/DD/YYYY"));
Live demo here
Note: Because you had "AUG" in your input string, you might need to tell the library to use English to parse the "MMM" part if your computer's locale does not use the English language.
Someday we will all speak ISO-8601. #rant :)
Use can use Date object method:
ToISOString()
This coverts date to string according to ISO standard
OR
Use :::toLocaleDateString()
You could use something like this:
var months={
"JAN":1,
"FEB":2,
//... other months
"DEC":12
}
var r=/(\d{1,2})\-(\w+)?\-(\d{1,2})/;
var replaceFunction=function(){
var years=parseInt(arguments[3],10);
var m=months[arguments[2]];
var days=arguments[1]
if(m<9){
m="0"+m;
}
if(days.length===1){
days="0"+days;
}
if(years>50){
years="19"+years;
}else{
years="20"+years;
}
return m+"/"+days+"/"+years;
};
console.log("5-JAN-14".replace(r,replaceFunction));
console.log("25-FEB-98".replace(r,replaceFunction));
You can use this JavaScript function to achieve that:
function formatDate(dateparam) {
var dateObj = new Date(Date.parse(dateparam));
var date = dateObj.getDate();
date = (date.toString().length == 1) ? "0" + date : date;
var month = dateObj.getMonth() + 1;
month = (month.toString().length == 1) ? "0" + month : month;
var year = dateObj.getFullYear();
return month + "/" + date + "/" + year;
}
document.write(formatDate("25-AUG-11"));
//returns "08/25/2011"
"Best" is relative and you haven't provided any criteria. Here's one way using plain string manipulation:
function reFormatDateString(s) {
s = s.split('-');
var months = {jan:'01', feb:'02', mar:'03', apr:'04', may:'05', jun:'06',
jul:'07', aug:'08', sep:'09', oct:'10', nov:'11', dec:'12'};
return months[s[1].toLowerCase()] + '/' + s[0] + '/' + s[2];
}
alert(reFormatDateString('25-AUG-11')); // 08/25/2011
However, likely you want to deal with the two digit year more specifically.
// The format "MM/DD/YYYY" isn't a "javascript" format, it's a US format.
function reFormatDateString1(s) {
s = s.split('-');
var months = {jan:'01', feb:'02', mar:'03', apr:'04', may:'05', jun:'06',
jul:'07', aug:'08', sep:'09', oct:'10', nov:'11', dec:'12'};
var m = +s[2];
s[2] = m < 100? (m < 50? m + 2000 : m + 1900) : m;
return months[s[1].toLowerCase()] + '/' + s[0] + '/' + s[2];
}
Here's another version that uses a date object:
function reFormatDateString2(s) {
s = s.split('-');
var months = {jan:0, feb:1, mar:2, apr:3, may:4, jun:5,
jul:6, aug:7, sep:8, oct:9, nov:10, dec:11};
function z(n){return (n<10? '0' : '') + n;}
// Convert 2 digit year. If < 50, assume 21st century,
// otherwise assume 20th.
// Adjust range to suit
if (s[2].length == 2) {
if (s[2] < 50 ) {
s[2] = +s[2] + 2000;
} else {
s[2] = +s[2] + 1900;
}
}
var d = new Date(s[2], months[s[1].toLowerCase()], s[0]);
return z(d.getMonth() + 1) + '/' + z(d.getMonth()+1) + '/' + z(d.getFullYear());
}
You choose "best".
This seems to be working fine.
var date = new Date("25-AUG-11");
console.log(date.getMonth() + '/' + date.getDate() + '/' + date.getFullYear());
Working Fiddle
You just need to add 0 at starting of month value which can be done easily with string length comparison.
Source