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Convert Date to a string of "YYYY-MM-DDTHH:MM:SS+HH:MM" format [duplicate]

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.

Javascript How can I get datetime string as "2017-05-23T00:03:21-05:00" [duplicate]

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.

How to parse date string in jQuery and check if it is in the past

I need to check if the date is in the past. This is what I have so far. JSfiddle here.
var date = "09/12/2013";
var d = new Date();
var month = d.getMonth() + 1;
var day = d.getDate();
var todaysDate = +(('' + day).length < 2 ? '0' : '') + day + '/' + (('' + month).length < 2 ? '0' : '') + month + '/' + d.getFullYear();
if (date < todaysDate) {
alert("in the past");
} else {
alert("in the future");
}
Currently it is saying that the date was in the past, when it should be in the future. I know I need to parse the string as a date, but not sure how.
Help?

With that input format, you can't use a string comparison, because the least significant values are on the left. Note: I'm assuing that date is December 9th, 2013. If you're doing the American thing where it's September 12th, 2013, you'll have to adjust the indexes into parts below.
You could reverse the fields:
var date = "09/12/2013";
var parts = date.split('/');
date = parts[2] + "/" + parts[1] + "/" + parts[0];
...and then do your string comparison (being sure to construct the string for "today" in the same order — year/month/day).
If you're going to do that, you could go ahead and finish the job
var date = "09/12/2013";
var parts = date.split('/');
var date = new Date(parseInt(parts[2], 10), // year
parseInt(parts[1], 10) - 1, // month, starts with 0
parseInt(parts[0], 10)); // day
if (date < new Date()) {
// It's in the past, including one millisecond ago
}
...but of course, if you don't want the expression to be true for one millisecond ago, your string approach is fine.

var date = new Date("09/12/2013");
var d = new Date();
console.log(date>d); // true
var date = new Date("09/12/2011");
console.log(date>d); // false

JavaScript's native Date comparator only works on Date objects, whereas you are comparing Strings. You should parse date into a Date object, and then compare it with d.
//define parse(string) --> Date
if(parse(date) < new Date()) {
alert('past');
} else {
alert('future');
}

How do I get Month and Date of JavaScript in 2 digit format?

When we call getMonth() and getDate() on date object, we will get the single digit number.
For example :
For january, it displays 1, but I need to display it as 01. How to do that?

("0" + this.getDate()).slice(-2)
for the date, and similar:
("0" + (this.getMonth() + 1)).slice(-2)
for the month.

If you want a format like "YYYY-MM-DDTHH:mm:ss", then this might be quicker:
var date = new Date().toISOString().substr(0, 19);
// toISOString() will give you YYYY-MM-DDTHH:mm:ss.sssZ
Or the commonly used MySQL datetime format "YYYY-MM-DD HH:mm:ss":
var date2 = new Date().toISOString().substr(0, 19).replace('T', ' ');

Why not use padStart ?
padStart(targetLength, padString) where
targetLength is 2
padString is 0
// Source: https://stackoverflow.com/a/50769505/2965993
var dt = new Date();
year = dt.getFullYear();
month = (dt.getMonth() + 1).toString().padStart(2, "0");
day = dt.getDate().toString().padStart(2, "0");
console.log(year + '/' + month + '/' + day);
This will always return 2 digit numbers even if the month or day is less than 10.
Notes:
This will only work with Internet Explorer if the js code is transpiled using babel.
getFullYear() returns the 4 digit year and doesn't require padStart.
getMonth() returns the month from 0 to 11.
1 is added to the month before padding to keep it 1 to 12.
getDate() returns the day from 1 to 31.
The 7th day will return 07 and so we do not need to add 1 before padding the string.

Example for month:
function getMonth(date) {
var month = date.getMonth() + 1;
return month < 10 ? '0' + month : '' + month; // ('' + month) for string result
}
You can also extend Date object with such function:
Date.prototype.getMonthFormatted = function() {
var month = this.getMonth() + 1;
return month < 10 ? '0' + month : '' + month; // ('' + month) for string result
}

The best way to do this is to create your own simple formatter (as below):
getDate() returns the day of the month (from 1-31)
getMonth() returns the month (from 0-11) < zero-based, 0=January, 11=December
getFullYear() returns the year (four digits) < don't use getYear()
function formatDateToString(date){
// 01, 02, 03, ... 29, 30, 31
var dd = (date.getDate() < 10 ? '0' : '') + date.getDate();
// 01, 02, 03, ... 10, 11, 12
var MM = ((date.getMonth() + 1) < 10 ? '0' : '') + (date.getMonth() + 1);
// 1970, 1971, ... 2015, 2016, ...
var yyyy = date.getFullYear();
// create the format you want
return (dd + "-" + MM + "-" + yyyy);
}

I would do this:
var date = new Date(2000, 0, 9);
var str = new Intl.DateTimeFormat('en-US', {
month: '2-digit',
day: '2-digit',
year: 'numeric'
}).format(date);
console.log(str); // prints "01/09/2000"

The following is used to convert db2 date format
i.e YYYY-MM-DD using ternary operator
var currentDate = new Date();
var twoDigitMonth=((currentDate.getMonth()+1)>=10)? (currentDate.getMonth()+1) : '0' + (currentDate.getMonth()+1);
var twoDigitDate=((currentDate.getDate())>=10)? (currentDate.getDate()) : '0' + (currentDate.getDate());
var createdDateTo = currentDate.getFullYear() + "-" + twoDigitMonth + "-" + twoDigitDate;
alert(createdDateTo);

Just another example, almost one liner.
var date = new Date();
console.log( (date.getMonth() < 9 ? '0': '') + (date.getMonth()+1) );

function monthFormated(date) {
//If date is not passed, get current date
if(!date)
date = new Date();
month = date.getMonth();
// if month 2 digits (9+1 = 10) don't add 0 in front
return month < 9 ? "0" + (month+1) : month+1;
}

If it might spare some time I was looking to get:
YYYYMMDD
for today, and got along with:
const dateDocumentID = new Date()
.toISOString()
.substr(0, 10)
.replace(/-/g, '');

function monthFormated() {
var date = new Date(),
month = date.getMonth();
return month+1 < 10 ? ("0" + month) : month;
}

This was my solution:
function leadingZero(value) {
if (value < 10) {
return "0" + value.toString();
}
return value.toString();
}
var targetDate = new Date();
targetDate.setDate(targetDate.getDate());
var dd = targetDate.getDate();
var mm = targetDate.getMonth() + 1;
var yyyy = targetDate.getFullYear();
var dateCurrent = leadingZero(mm) + "/" + leadingZero(dd) + "/" + yyyy;

Using Moment.js it can be done like that:
moment(new Date(2017, 1, 1)).format('DD') // day
moment(new Date(2017, 1, 1)).format('MM') // month

const today = new Date().toISOString()
const fullDate = today.split('T')[0];
console.log(fullDate) //prints YYYY-MM-DD

Not an answer but here is how I get the date format I require in a variable
function setDateZero(date){
return date < 10 ? '0' + date : date;
}
var curr_date = ev.date.getDate();
var curr_month = ev.date.getMonth() + 1;
var curr_year = ev.date.getFullYear();
var thisDate = curr_year+"-"+setDateZero(curr_month)+"-"+setDateZero(curr_date);
Hope this helps!

Ternary Operator Solution
A simple ternary operator can add a "0" before the number if the month or day is less than 10 (assuming you need this information for use in a string).
let month = (date.getMonth() < 10) ? "0" + date.getMonth().toString() : date.getMonth();
let day = (date.getDate() < 10) ? "0" + date.getDate().toString() : date.getDate();

The more modern approach perhaps, using "padStart"
const now = new Date();
const day = `${now.getDate()}`.padStart(2, '0');
const month = `${now.getMonth()}`.padStart(2, '0');
const year = now.getFullYear();
then you can build as a template string if you wish:
`${day}/${month}/${year}`

Tip from MDN :
function date_locale(thisDate, locale) {
if (locale == undefined)
locale = 'fr-FR';
// set your default country above (yes, I'm french !)
// then the default format is "dd/mm/YYY"
if (thisDate == undefined) {
var d = new Date();
} else {
var d = new Date(thisDate);
}
return d.toLocaleDateString(locale);
}
var thisDate = date_locale();
var dayN = thisDate.slice(0, 2);
var monthN = thisDate.slice(3, 5);
console.log(dayN);
console.log(monthN);
http://jsfiddle.net/v4qcf5x6/

new Date().getMonth() method returns the month as a number (0-11)
You can get easily correct month number with this function.
function monthFormatted() {
var date = new Date(),
month = date.getMonth();
return month+1 < 10 ? ("0" + month) : month;
}

I would suggest you use a different library called Moment https://momentjs.com/
This way you are able to format the date directly without having to do extra work
const date = moment().format('YYYY-MM-DD')
// date: '2020-01-04'
Make sure you import moment as well to be able to use it.
yarn add moment
# to add the dependency
import moment from 'moment'
// import this at the top of the file you want to use it in
Hope this helps :D

How it easy?
new Date().toLocaleString("en-US", { day: "2-digit" })
Another options are available such:
weekday
year
month
More info here.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString#using_options

function GetDateAndTime(dt) {
var arr = new Array(dt.getDate(), dt.getMonth(), dt.getFullYear(),dt.getHours(),dt.getMinutes(),dt.getSeconds());
for(var i=0;i<arr.length;i++) {
if(arr[i].toString().length == 1) arr[i] = "0" + arr[i];
}
return arr[0] + "." + arr[1] + "." + arr[2] + " " + arr[3] + ":" + arr[4] + ":" + arr[5];
}

And another version here https://jsfiddle.net/ivos/zcLxo8oy/1/, hope to be useful.
var dt = new Date(2016,5,1); // just for the test
var separator = '.';
var strDate = (dt.getFullYear() + separator + (dt.getMonth() + 1) + separator + dt.getDate());
// end of setup
strDate = strDate.replace(/(\b\d{1}\b)/g, "0$1")

The answers here were helpful, however I need more than that: not only month, date, month, hours & seconds, for a default name.
Interestingly, though prepend of "0" was needed for all above, " + 1" was needed only for month, not others.
As example:
("0" + (d.getMonth() + 1)).slice(-2) // Note: +1 is needed
("0" + (d.getHours())).slice(-2) // Note: +1 is not needed

My solution:
function addLeadingChars(string, nrOfChars, leadingChar) {
string = string + '';
return Array(Math.max(0, (nrOfChars || 2) - string.length + 1)).join(leadingChar || '0') + string;
}
Usage:
var
date = new Date(),
month = addLeadingChars(date.getMonth() + 1),
day = addLeadingChars(date.getDate());
jsfiddle: http://jsfiddle.net/8xy4Q/1/

var net = require('net')
function zeroFill(i) {
return (i < 10 ? '0' : '') + i
}
function now () {
var d = new Date()
return d.getFullYear() + '-'
+ zeroFill(d.getMonth() + 1) + '-'
+ zeroFill(d.getDate()) + ' '
+ zeroFill(d.getHours()) + ':'
+ zeroFill(d.getMinutes())
}
var server = net.createServer(function (socket) {
socket.end(now() + '\n')
})
server.listen(Number(process.argv[2]))

if u want getDate() function to return the date as 01 instead of 1, here is the code for it....
Lets assume Today's date is 01-11-2018
var today = new Date();
today = today.getFullYear()+ "-" + (today.getMonth() + 1) + "-" + today.getDate();
console.log(today); //Output: 2018-11-1
today = today.getFullYear()+ "-" + (today.getMonth() + 1) + "-" + ((today.getDate() < 10 ? '0' : '') + today.getDate());
console.log(today); //Output: 2018-11-01

I wanted to do something like this and this is what i did
p.s. i know there are right answer(s) on top, but just wanted to add something of my own here
const todayIs = async () =>{
const now = new Date();
var today = now.getFullYear()+'-';
if(now.getMonth() < 10)
today += '0'+now.getMonth()+'-';
else
today += now.getMonth()+'-';
if(now.getDay() < 10)
today += '0'+now.getDay();
else
today += now.getDay();
return today;
}

If you'll check smaller than 10, you haven't to create a new function for that. Just assign a variable into brackets and return it with ternary operator.
(m = new Date().getMonth() + 1) < 10 ? `0${m}` : `${m}`

currentDate(){
var today = new Date();
var dateTime = today.getFullYear()+'-'+
((today.getMonth()+1)<10?("0"+(today.getMonth()+1)):(today.getMonth()+1))+'-'+
(today.getDate()<10?("0"+today.getDate()):today.getDate())+'T'+
(today.getHours()<10?("0"+today.getHours()):today.getHours())+ ":" +
(today.getMinutes()<10?("0"+today.getMinutes()):today.getMinutes())+ ":" +
(today.getSeconds()<10?("0"+today.getSeconds()):today.getSeconds());
return dateTime;
},

Javascript add leading zeroes to date

I've created this script to calculate the date for 10 days in advance in the format of dd/mm/yyyy:
var MyDate = new Date();
var MyDateString = new Date();
MyDate.setDate(MyDate.getDate()+10);
MyDateString = MyDate.getDate() + '/' + (MyDate.getMonth()+1) + '/' + MyDate.getFullYear();
I need to have the date appear with leading zeroes on the day and month component by way of adding these rules to the script. I can't seem to get it to work.
if (MyDate.getMonth < 10)getMonth = '0' + getMonth;
and
if (MyDate.getDate <10)get.Date = '0' + getDate;
If someone could show me where to insert these into the script I would be really appreciative.

Try this: http://jsfiddle.net/xA5B7/
var MyDate = new Date();
var MyDateString;
MyDate.setDate(MyDate.getDate() + 20);
MyDateString = ('0' + MyDate.getDate()).slice(-2) + '/'
+ ('0' + (MyDate.getMonth()+1)).slice(-2) + '/'
+ MyDate.getFullYear();
EDIT:
To explain, .slice(-2) gives us the last two characters of the string.
So no matter what, we can add "0" to the day or month, and just ask for the last two since those are always the two we want.
So if the MyDate.getMonth() returns 9, it will be:
("0" + "9") // Giving us "09"
so adding .slice(-2) on that gives us the last two characters which is:
("0" + "9").slice(-2)
"09"
But if MyDate.getMonth() returns 10, it will be:
("0" + "10") // Giving us "010"
so adding .slice(-2) gives us the last two characters, or:
("0" + "10").slice(-2)
"10"

The modern way
The new modern way to do this is to use toLocaleDateString, because it allows you not only to format a date with proper localization, but even to pass format options to achieve the desired result:
const date = new Date(2018, 2, 1)
const result = date.toLocaleDateString("en-GB", { // you can use undefined as first argument
year: "numeric",
month: "2-digit",
day: "2-digit",
})
console.log(result) // outputs “01/03/2018”
Or using a Temporal object (still in proposal, caniuse):
const date = new Temporal.PlainDate(2018, 3, 1) // also works with zoned date
const result = date.toLocaleString("en-GB", { // you can use undefined as first argument
year: "numeric",
month: "2-digit",
day: "2-digit",
})
console.log(result) // outputs “01/03/2018”
When you use undefined as the first argument it will detect the browser language, instead. Alternatively, you can use 2-digit on the year option, too.
Performance
If you plan to format a lot of dates, you should consider using Intl.DateTimeFormat instead:
const formatter = new Intl.DateTimeFormat("en-GB", { // <- re-use me
year: "numeric",
month: "2-digit",
day: "2-digit",
})
const date = new Date(2018, 2, 1) // can also be a Temporal object
const result = formatter.format(date)
console.log(result) // outputs “01/03/2018”
The formatter is compatible with Date and Temporal objects.
Historical dates
Unlike in the Temporal constructor years between 0 and 99 will be interpreted as 20th century years on the Date constructor. To prevent this, initialize the date like so:
const date = new Date()
date.setFullYear(18, 2, 1) // the year is A.D. 18
This is not required for Temporal objects, but years below 1000 will not contain leading zeros in all cases, because the formatter (that is shared for the Date and Temporal API) does not support 4-digit formatting at all. In this case you have to do manual formatting (see below).
For the ISO 8601 format
If you want to get your date in the YYYY-MM-DD format (ISO 8601), the solution looks different:
const date = new Date(Date.UTC(2018, 2, 1))
const result = date.toISOString().split('T')[0]
console.log(result) // outputs “2018-03-01”
Your input date should be in the UTC format or toISOString() will fix that for you. This is done by using Date.UTC as shown above.
Historical dates for the ISO 8601 format
Unlike in the Temporal constructor years between 0 and 99 will be interpreted as 20th century years on the Date constructor. To prevent this, initialize the date like so to be used for the ISO 8601 format:
const date = new Date()
date.setUTCFullYear(18, 2, 1) // the year is A.D. 18
Note that the ISO format for Temporal objects with dates before the year 1000 or after the year 9999 will have a different formatting compared to the legacy Date API. It is recommend to fallback to custom formatting to enforce 4 digit years in all circumstances.
Custom 4-digit formatting on the year
Sadly, the formatter doesn't support leading zeros on the year. There is no 4-digit option. This will remain for Temporal objects as well, because they do share the same formatter.
Fortunately, the ISO format of the Date API will always display at least 4 digits on the year, although Temporal objects do not. So at least for the Date API you can format historical dates before the year 1000 with leading zeros by falling back to a manual formatting approach using part of the ISO 8601 format method:
const date = new Date()
date.setUTCFullYear(18, 2, 1)
const ymd = date.toISOString().split('T')[0].split('-')
const result = `${ymd[2]}/${ymd[1]}/${ymd[0]}`
console.log(result) // outputs “01/03/0018”
For a Temporal object a different route is necessary, since the ISOYearString will be formatted differently for dates before the year 1000 and after the year 9999 as mentioned before:
const date = new Temporal.PlainDate(2018, 3, 1) // also works with zoned date
const zeroPad = (n, digits) => n.toString().padStart(digits, '0');
const result = `${zeroPad(date.day, 2)}/${zeroPad(date.month, 2)}/${zeroPad(date.year, 4)}`;
console.log(result) // outputs “01/03/0018”
Miscellaneous
For the Date and Temporal API there is also toLocaleTimeString, that allows you to localize and format the time of a date.

Here is an example from the Date object docs on the Mozilla Developer Network using a custom "pad" function, without having to extend Javascript's Number prototype. The handy function they give as an example is
function pad(n){return n<10 ? '0'+n : n}
And below is it being used in context.
/* use a function for the exact format desired... */
function ISODateString(d){
function pad(n){return n<10 ? '0'+n : n}
return d.getUTCFullYear()+'-'
+ pad(d.getUTCMonth()+1)+'-'
+ pad(d.getUTCDate())+'T'
+ pad(d.getUTCHours())+':'
+ pad(d.getUTCMinutes())+':'
+ pad(d.getUTCSeconds())+'Z'
}
var d = new Date();
console.log(ISODateString(d)); // prints something like 2009-09-28T19:03:12Z

For you people from the future (ECMAScript 2017 and beyond)
Solution
"use strict"
const today = new Date()
const year = today.getFullYear()
const month = `${today.getMonth() + 1}`.padStart(2, "0")
const day = `${today.getDate()}`.padStart(2, "0")
const stringDate = [day, month, year].join("/") // 13/12/2017
Explaination
the String.prototype.padStart(targetLength[, padString]) adds as many as possible padString in the String.prototype target so that the new length of the target is targetLength.
Example
"use strict"
let month = "9"
month = month.padStart(2, "0") // "09"
let byte = "00000100"
byte = byte.padStart(8, "0") // "00000100"

You can define a "str_pad" function (as in php):
function str_pad(n) {
return String("00" + n).slice(-2);
}

I found the shorterst way to do this:
MyDateString.replace(/(^|\D)(\d)(?!\d)/g, '$10$2');
will add leading zeros to all lonely, single digits

Number.prototype.padZero= function(len){
var s= String(this), c= '0';
len= len || 2;
while(s.length < len) s= c + s;
return s;
}
//in use:
(function(){
var myDate= new Date(), myDateString;
myDate.setDate(myDate.getDate()+10);
myDateString= [myDate.getDate().padZero(),
(myDate.getMonth()+1).padZero(),
myDate.getFullYear()].join('/');
alert(myDateString);
})()
/* value: (String)
09/09/2010
*/

Nowadays you can also utilize String.prototype.padStart to reach the goal in quick and easy way
String(new Date().getMonth() + 1).padStart(2, '0')
The availability can be assessed at caniuse
var date = new Date()
var year = date.getFullYear()
var month = String(date.getMonth() + 1).padStart(2, '0')
var day = String(date.getDate()).padStart(2, '0')
console.log('%s/%s/%s', month, day, year)
Check
var date = new Date('7/4/2021')
var year = date.getFullYear()
var month = String(date.getMonth() + 1).padStart(2, '0')
var day = String(date.getDate()).padStart(2, '0')
/**
* Expected output: 07/04/2021
*/
console.log('%s/%s/%s', month, day, year)
Polyfill for old browsers
String.prototype.padStart || Object.defineProperty(String.prototype, 'padStart', {
configurable : true,
writable : true,
value : function (targetLength, padString) {
'use strict'
/**
* String.prototype.padStart polyfill
* https://stackoverflow.com/questions/3605214/javascript-add-leading-zeroes-to-date
*/
targetLength = targetLength | 0
padString = arguments.length > 1 ? String(padString) : ' '
if (this.length < targetLength && padString.length) {
targetLength = targetLength - this.length
while (padString.length < targetLength) {
padString += padString
}
return padString.slice(0, targetLength) + this
} else {
return this
}
}
})

var MyDate = new Date();
var MyDateString = '';
MyDate.setDate(MyDate.getDate());
var tempoMonth = (MyDate.getMonth()+1);
var tempoDate = (MyDate.getDate());
if (tempoMonth < 10) tempoMonth = '0' + tempoMonth;
if (tempoDate < 10) tempoDate = '0' + tempoDate;
MyDateString = tempoDate + '/' + tempoMonth + '/' + MyDate.getFullYear();

There is another approach to solve this problem, using slice in JavaScript.
var d = new Date();
var datestring = d.getFullYear() + "-" + ("0"+(d.getMonth()+1)).slice(-2) +"-"+("0" + d.getDate()).slice(-2);
the datestring return date with format as you expect: 2019-09-01
another approach is using dateformat library: https://github.com/felixge/node-dateformat

You could use ternary operator to format the date like an "if" statement.
For example:
var MyDate = new Date();
MyDate.setDate(MyDate.getDate()+10);
var MyDateString = (MyDate.getDate() < 10 ? '0' + MyDate.getDate() : MyDate.getDate()) + '/' + ((d.getMonth()+1) < 10 ? '0' + (d.getMonth()+1) : (d.getMonth()+1)) + '/' + MyDate.getFullYear();
So
(MyDate.getDate() < 10 ? '0' + MyDate.getDate() : MyDate.getDate())
would be similar to an if statement, where if the getDate() returns a value less than 10, then return a '0' + the Date, or else return the date if greater than 10 (since we do not need to add the leading 0). Same for the month.
Edit:
Forgot that getMonth starts with 0, so added the +1 to account for it. Of course you could also just say d.getMonth() < 9 :, but I figured using the +1 would help make it easier to understand.

function formatDate(jsDate){
// add leading zeroes to jsDate when days or months are < 10..
// i.e.
// formatDate(new Date("1/3/2013"));
// returns
// "01/03/2103"
////////////////////
return (jsDate.getDate()<10?("0"+jsDate.getDate()):jsDate.getDate()) + "/" +
((jsDate.getMonth()+1)<10?("0"+(jsDate.getMonth()+1)):(jsDate.getMonth()+1)) + "/" +
jsDate.getFullYear();
}

You can provide options as a parameter to format date. First parameter is for locale which you might not need and second is for options.
For more info visit
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString
var date = new Date(Date.UTC(2012, 1, 1, 3, 0, 0));
var options = { year: 'numeric', month: '2-digit', day: '2-digit' };
console.log(date.toLocaleDateString(undefined,options));

I wrapped the correct answer of this question in a function that can add multiple leading zero's but defaults to adding 1 zero.
function zeroFill(nr, depth){
depth = (depth === undefined)? 1 : depth;
var zero = "0";
for (var i = 0; i < depth; ++i) {
zero += "0";
}
return (zero + nr).slice(-(depth + 1));
}
for working with numbers only and not more than 2 digits, this is also an approach:
function zeroFill(i) {
return (i < 10 ? '0' : '') + i
}

Another option, using a built-in function to do the padding (but resulting in quite long code!):
myDateString = myDate.getDate().toLocaleString('en-US', {minimumIntegerDigits: 2})
+ '/' + (myDate.getMonth()+1).toLocaleString('en-US', {minimumIntegerDigits: 2})
+ '/' + myDate.getFullYear();
// '12/06/2017'
And another, manipulating strings with regular expressions:
var myDateString = myDate.toISOString().replace(/T.*/, '').replace(/-/g, '/');
// '2017/06/12'
But be aware that one will show the year at the start and the day at the end.

Adding on to #modiX answer, this is what works...DO NOT LEAVE THAT as empty
today.toLocaleDateString("default", {year: "numeric", month: "2-digit", day: "2-digit"})

Here is very simple example how you can handle this situation.
var mydate = new Date();
var month = (mydate.getMonth().toString().length < 2 ? "0"+mydate.getMonth().toString() :mydate.getMonth());
var date = (mydate.getDate().toString().length < 2 ? "0"+mydate.getDate().toString() :mydate.getDate());
var year = mydate.getFullYear();
console.log("Format Y-m-d : ",year+"-"+month+"-" + date);
console.log("Format Y/m/d : ",year+"/"+month+"/" + date);

I think this solution is easier and can be easily remembered:
var MyDate = new Date();
var day = MyDate.getDate() + 10; // 10 days in advance
var month = MyDate.getMonth() + 1; // since months start from 0 we should add 1 to it
var year = MyDate.getFullYear();
day = checkDate(day);
month = checkDate(month);
function checkDate(i){
if(i < 10){
i = '0' + i;
}
return i;
}
console.log(`${month}/${day}/${year}`);

What I would do, is create my own custom Date helper that looks like this :
var DateHelper = {
addDays : function(aDate, numberOfDays) {
aDate.setDate(aDate.getDate() + numberOfDays); // Add numberOfDays
return aDate; // Return the date
},
format : function format(date) {
return [
("0" + date.getDate()).slice(-2), // Get day and pad it with zeroes
("0" + (date.getMonth()+1)).slice(-2), // Get month and pad it with zeroes
date.getFullYear() // Get full year
].join('/'); // Glue the pieces together
}
}
// With this helper, you can now just use one line of readable code to :
// ---------------------------------------------------------------------
// 1. Get the current date
// 2. Add 20 days
// 3. Format it
// 4. Output it
// ---------------------------------------------------------------------
document.body.innerHTML = DateHelper.format(DateHelper.addDays(new Date(), 20));
(see also this Fiddle)

As #John Henckel suggests, starting using the toISOString() method makes things easier
const dateString = new Date().toISOString().split('-');
const year = dateString[0];
const month = dateString[1];
const day = dateString[2].split('T')[0];
console.log(`${year}-${month}-${day}`);

try this for a basic function, no libraries required
Date.prototype.CustomformatDate = function() {
var tmp = new Date(this.valueOf());
var mm = tmp.getMonth() + 1;
if (mm < 10) mm = "0" + mm;
var dd = tmp.getDate();
if (dd < 10) dd = "0" + dd;
return mm + "/" + dd + "/" + tmp.getFullYear();
};

You could simply use :
const d = new Date();
const day = `0${d.getDate()}`.slice(-2);
So a function could be created like :
AddZero(val){
// adding 0 if the value is a single digit
return `0${val}`.slice(-2);
}
Your new code :
var MyDate = new Date();
var MyDateString = new Date();
MyDate.setDate(MyDate.getDate()+10);
MyDateString = AddZero(MyDate.getDate()) + '/' + AddZero(MyDate.getMonth() + 1) + '/' + MyDate.getFullYear();

toISOString can get leading 0
const currentdate = new Date();
const date = new Date(Date.UTC(currentdate.getFullYear(), (currentdate.getMonth()),currentdate.getDate(), currentdate.getHours(), currentdate.getMinutes(), currentdate.getSeconds()));
//you can pass YY, MM, DD //op: 2018-03-01
//i have passed YY, MM, DD, HH, Min, Sec // op : 2021-06-09T12:14:27.000Z
console.log(date.toISOString());
output will be similar to this : 2021-06-09T12:14:27.000Z

const month = date.toLocaleDateString('en-US', { month: '2-digit' });
const day = date.toLocaleDateString('en-US', { day: '2-digit' });
const year = date.getFullYear();
const dateString = `${month}-${day}-${year}`;

The following aims to extract configuration, hook into Date.protoype and apply configuration.
I've used an Array to store time chunks and when I push() this as a Date object, it returns me the length to iterate. When I'm done, I can use join on the return value.
This seems to work pretty fast: 0.016ms
// Date protoype
Date.prototype.formatTime = function (options) {
var i = 0,
time = [],
len = time.push(this.getHours(), this.getMinutes(), this.getSeconds());
for (; i < len; i += 1) {
var tick = time[i];
time[i] = tick < 10 ? options.pad + tick : tick;
}
return time.join(options.separator);
};
// Setup output
var cfg = {
fieldClock: "#fieldClock",
options: {
pad: "0",
separator: ":",
tick: 1000
}
};
// Define functionality
function startTime() {
var clock = $(cfg.fieldClock),
now = new Date().formatTime(cfg.options);
clock.val(now);
setTimeout(startTime, cfg.options.tick);
}
// Run once
startTime();
demo: http://jsfiddle.net/tive/U4MZ3/

Add some padding to allow a leading zero - where needed - and concatenate using your delimiter of choice as string.
Number.prototype.padLeft = function(base,chr){
var len = (String(base || 10).length - String(this).length)+1;
return len > 0? new Array(len).join(chr || '0')+this : this;
}
var d = new Date(my_date);
var dformatted = [(d.getMonth()+1).padLeft(), d.getDate().padLeft(), d.getFullYear()].join('/');

let date = new Date();
let dd = date.getDate();//day of month
let mm = date.getMonth();// month
let yyyy = date.getFullYear();//day of week
if (dd < 10) {//if less then 10 add a leading zero
dd = "0" + dd;
}
if (mm < 10) {
mm = "0" + mm;//if less then 10 add a leading zero
}

function pad(value) {
return value.tostring().padstart(2, 0);
}
let d = new date();
console.log(d);
console.log(`${d.getfullyear()}-${pad(d.getmonth() + 1)}-${pad(d.getdate())}t${pad(d.gethours())}:${pad(d.getminutes())}:${pad(d.getseconds())}`);

You can use String.slice() which extracts a section of a string and returns it as a new string, without modifying the original string:
const currentDate = new Date().toISOString().slice(0, 10) // 2020-04-16
Or you can also use a lib such as Moment.js to format the date:
const moment = require("moment")
const currentDate = moment().format("YYYY-MM-DD") // 2020-04-16

A simple dateformat library saved my life (GitHub):
Node.js: var dateFormat = require("dateformat");
ES6: import dateFormat from "dateformat";
const now = new Date(); // consider 3rd of December 1993
const full = dateFormat(today, "yyyy-mm-dd"); // 1993-12-03
const day = dateFormat(today, "dd"); // 03
const month = dateFormat(today, "mm"); // 12
const year = dateFormat(today, "yyyy"); // 1993
It's worth to mention it supports a wide range of mask options.