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Put clock forward by one hour [duplicate]

It amazes me that JavaScript's Date object does not implement an add function of any kind.
I simply want a function that can do this:
var now = Date.now();
var fourHoursLater = now.addHours(4);
function Date.prototype.addHours(h) {
// How do I implement this?
}
I would simply like some pointers in a direction.
Do I need to do string parsing?
Can I use setTime?
How about milliseconds?
Like this:
new Date(milliseconds + 4*3600*1000 /* 4 hours in ms */)?
This seems really hackish though - and does it even work?

JavaScript itself has terrible Date/Time API's. Nonetheless, you can do this in pure JavaScript:
Date.prototype.addHours = function(h) {
this.setTime(this.getTime() + (h*60*60*1000));
return this;
}

Date.prototype.addHours= function(h){
this.setHours(this.getHours()+h);
return this;
}
Test:
alert(new Date().addHours(4));

The below code will add 4 hours to a date (example, today's date):
var today = new Date();
today.setHours(today.getHours() + 4);
It will not cause an error if you try to add 4 to 23 (see the documentation):
If a parameter you specify is outside of the expected range, setHours() attempts to update the date information in the Date object accordingly

It is probably better to make the addHours method immutable by returning a copy of the Date object rather than mutating its parameter.
Date.prototype.addHours= function(h){
var copiedDate = new Date(this.getTime());
copiedDate.setHours(copiedDate.getHours()+h);
return copiedDate;
}
This way you can chain a bunch of method calls without worrying about state.

The version suggested by kennebec will fail when changing to or from DST, since it is the hour number that is set.
this.setUTCHours(this.getUTCHours()+h);
will add h hours to this independent of time system peculiarities.
Jason Harwig's method works as well.

Get a date exactly two hours from now, in one line.
You need to pass milliseconds to new Date.
let expiryDate = new Date(new Date().setHours(new Date().getHours() + 2));
or
let expiryDate2 = new Date(Date.now() + 2 * (60 * 60 * 1000) );
let nowDate = new Date();
let expiryDate = new Date(new Date().setHours(new Date().getHours() + 2));
let expiryDate2 = new Date(Date.now() + 2 * (60 * 60 * 1000) );
console.log('now', nowDate);
console.log('expiry', expiryDate);
console.log('expiry 2', expiryDate2);

You can use the Moment.js library.
var moment = require('moment');
foo = new moment(something).add(10, 'm').toDate();

I also think the original object should not be modified. So to save future manpower here's a combined solution based on Jason Harwig's and Tahir Hasan answers:
Date.prototype.addHours= function(h){
var copiedDate = new Date();
copiedDate.setTime(this.getTime() + (h*60*60*1000));
return copiedDate;
}

If you would like to do it in a more functional way (immutability) I would return a new date object instead of modifying the existing and I wouldn't alter the prototype but create a standalone function. Here is the example:
//JS
function addHoursToDate(date, hours) {
return new Date(new Date(date).setHours(date.getHours() + hours));
}
//TS
function addHoursToDate(date: Date, hours: number): Date {
return new Date(new Date(date).setHours(date.getHours() + hours));
}
let myDate = new Date();
console.log(myDate)
console.log(addHoursToDate(myDate,2))

There is an add in the Datejs library.
And here are the JavaScript date methods. kennebec wisely mentioned getHours() and setHours();

Check if it’s not already defined. Otherwise, define it in the Date prototype:
if (!Date.prototype.addHours) {
Date.prototype.addHours = function(h) {
this.setHours(this.getHours() + h);
return this;
};
}

This is an easy way to get an incremented or decremented data value.
const date = new Date()
const inc = 1000 * 60 * 60 // an hour
const dec = (1000 * 60 * 60) * -1 // an hour
const _date = new Date(date)
return new Date(_date.getTime() + inc)
return new Date(_date.getTime() + dec)

Another way to handle this is to convert the date to unixtime (epoch), then add the equivalent in (milli)seconds, then convert it back. This way you can handle day and month transitions, like adding 4 hours to 21, which should result in the next day, 01:00.

SPRBRN is correct. In order to account for the beginning/end of the month and year, you need to convert to Epoch and back.
Here's how you do that:
var milliseconds = 0; //amount of time from current date/time
var sec = 0; //(+): future
var min = 0; //(-): past
var hours = 2;
var days = 0;
var startDate = new Date(); //start date in local time (we'll use current time as an example)
var time = startDate.getTime(); //convert to milliseconds since epoch
//add time difference
var newTime = time + milliseconds + (1000*sec) + (1000*60*min) + (1000*60*60*hrs) + (1000*60*60*24*days);
var newDate = new Date(newTime); //convert back to date; in this example: 2 hours from right now
Or do it in one line (where variable names are the same as above:
var newDate =
new Date(startDate.getTime() + millisecond +
1000 * (sec + 60 * (min + 60 * (hours + 24 * days))));

For a simple add/subtract hour/minute function in JavaScript, try this:
function getTime (addHour, addMin){
addHour = (addHour ? addHour : 0);
addMin = (addMin ? addMin : 0);
var time = new Date(new Date().getTime());
var AM = true;
var ndble = 0;
var hours, newHour, overHour, newMin, overMin;
// Change form 24 to 12 hour clock
if(time.getHours() >= 13){
hours = time.getHours() - 12;
AM = (hours>=12 ? true : false);
}else{
hours = time.getHours();
AM = (hours>=12 ? false : true);
}
// Get the current minutes
var minutes = time.getMinutes();
// Set minute
if((minutes + addMin) >= 60 || (minutes + addMin) < 0){
overMin = (minutes + addMin) % 60;
overHour = Math.floor((minutes + addMin - Math.abs(overMin))/60);
if(overMin < 0){
overMin = overMin + 60;
overHour = overHour-Math.floor(overMin/60);
}
newMin = String((overMin<10 ? '0' : '') + overMin);
addHour = addHour + overHour;
}else{
newMin = minutes + addMin;
newMin = String((newMin<10 ? '0' : '') + newMin);
}
// Set hour
if((hours + addHour >= 13) || (hours + addHour <= 0)){
overHour = (hours + addHour) % 12;
ndble = Math.floor(Math.abs((hours + addHour)/12));
if(overHour <= 0){
newHour = overHour + 12;
if(overHour == 0){
ndble++;
}
}else{
if(overHour == 0){
newHour = 12;
ndble++;
}else{
ndble++;
newHour = overHour;
}
}
newHour = (newHour<10 ? '0' : '') + String(newHour);
AM = ((ndble + 1) % 2 === 0) ? AM : !AM;
}else{
AM = (hours + addHour == 12 ? !AM : AM);
newHour = String((Number(hours) + addHour < 10 ? '0': '') + (hours + addHour));
}
var am = (AM) ? 'AM' : 'PM';
return new Array(newHour, newMin, am);
};
This can be used without parameters to get the current time:
getTime();
Or with parameters to get the time with the added minutes/hours:
getTime(1, 30); // Adds 1.5 hours to current time
getTime(2); // Adds 2 hours to current time
getTime(0, 120); // Same as above
Even negative time works:
getTime(-1, -30); // Subtracts 1.5 hours from current time
This function returns an array of:
array([Hour], [Minute], [Meridian])

If you need it as a string, for example:
var defaultTime: new Date().getHours() + 1 + ":" + new Date().getMinutes();

I think this should do the trick
var nextHour = Date.now() + 1000 * 60 * 60;
console.log(nextHour)

You can even format the date in desired format using the moment function after adding 2 hours.
var time = moment(new Date(new Date().setHours(new Date().getHours() + 2))).format("YYYY-MM-DD");
console.log(time);

A little messy, but it works!
Given a date format like this: 2019-04-03T15:58
//Get the start date.
var start = $("#start_date").val();
//Split the date and time.
var startarray = start.split("T");
var date = startarray[0];
var time = startarray[1];
//Split the hours and minutes.
var timearray = time.split(":");
var hour = timearray[0];
var minute = timearray[1];
//Add an hour to the hour.
hour++;
//$("#end_date").val = start;
$("#end_date").val(""+date+"T"+hour+":"+minute+"");
Your output would be: 2019-04-03T16:58

The easiest way to do it is:
var d = new Date();
d = new Date(d.setHours(d.getHours() + 2));
It will add 2 hours to the current time.
The value of d = Sat Jan 30 2021 23:41:43 GMT+0500 (Pakistan Standard Time).
The value of d after adding 2 hours = Sun Jan 31 2021 01:41:43 GMT+0500 (Pakistan Standard Time).

Change time stamp from unix to MM/DD/YYY in a multidimensional array [duplicate]

I am storing time in a MySQL database as a Unix timestamp and that gets sent to some JavaScript code. How would I get just the time out of it?
For example, in HH/MM/SS format.

let unix_timestamp = 1549312452
// Create a new JavaScript Date object based on the timestamp
// multiplied by 1000 so that the argument is in milliseconds, not seconds.
var date = new Date(unix_timestamp * 1000);
// Hours part from the timestamp
var hours = date.getHours();
// Minutes part from the timestamp
var minutes = "0" + date.getMinutes();
// Seconds part from the timestamp
var seconds = "0" + date.getSeconds();
// Will display time in 10:30:23 format
var formattedTime = hours + ':' + minutes.substr(-2) + ':' + seconds.substr(-2);
console.log(formattedTime);
For more information regarding the Date object, please refer to MDN or the ECMAScript 5 specification.

function timeConverter(UNIX_timestamp){
var a = new Date(UNIX_timestamp * 1000);
var months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
var year = a.getFullYear();
var month = months[a.getMonth()];
var date = a.getDate();
var hour = a.getHours();
var min = a.getMinutes();
var sec = a.getSeconds();
var time = date + ' ' + month + ' ' + year + ' ' + hour + ':' + min + ':' + sec ;
return time;
}
console.log(timeConverter(0));

JavaScript works in milliseconds, so you'll first have to convert the UNIX timestamp from seconds to milliseconds.
var date = new Date(UNIX_Timestamp * 1000);
// Manipulate JavaScript Date object here...

Use:
var s = new Date(1504095567183).toLocaleDateString("en-US")
console.log(s)
// expected output "8/30/2017"
and for time:
var s = new Date(1504095567183).toLocaleTimeString("en-US")
console.log(s)
// expected output "3:19:27 PM"
see Date.prototype.toLocaleDateString()

Modern Solution (for 2020)
In the new world, we should be moving towards the standard Intl JavaScript object, that has a handy DateTimeFormat constructor with .format() method:
function format_time(s) {
const dtFormat = new Intl.DateTimeFormat('en-GB', {
timeStyle: 'medium',
timeZone: 'UTC'
});
return dtFormat.format(new Date(s * 1e3));
}
console.log( format_time(12345) ); // "03:25:45"
Eternal Solution
But to be 100% compatible with all legacy JavaScript engines, here is the shortest one-liner solution to format seconds as hh:mm:ss:
function format_time(s) {
return new Date(s * 1e3).toISOString().slice(-13, -5);
}
console.log( format_time(12345) ); // "03:25:45"
Method Date.prototype.toISOString() returns time in
simplified extended ISO 8601 format, which is always 24 or 27 characters long (i.e. YYYY-MM-DDTHH:mm:ss.sssZ or
±YYYYYY-MM-DDTHH:mm:ss.sssZ respectively). The timezone is always
zero UTC offset.
This solution does not require any third-party libraries and is supported in all browsers and JavaScript engines.

I'm partial to Jacob Wright's Date.format() library, which implements JavaScript date formatting in the style of PHP's date() function.
new Date(unix_timestamp * 1000).format('h:i:s')

I'd think about using a library like momentjs.com, that makes this really simple:
Based on a Unix timestamp:
var timestamp = moment.unix(1293683278);
console.log( timestamp.format("HH/mm/ss") );
Based on a MySQL date string:
var now = moment("2010-10-10 12:03:15");
console.log( now.format("HH/mm/ss") );

shortest one-liner solution to format seconds as hh:mm:ss: variant:
console.log(new Date(1549312452 * 1000).toISOString().slice(0, 19).replace('T', ' '));
// "2019-02-04 20:34:12"

In moment you must use unix timestamp:
const dateTimeString = moment.unix(1466760005).format("DD-MM-YYYY HH:mm:ss");

This works with PHP timestamps
var d = 1541415288860;
//var d =val.timestamp;
//NB: use + before variable name
var date = new Date(+d);
console.log(d);
console.log(date.toDateString());
console.log(date.getFullYear());
console.log(date.getMinutes());
console.log(date.getSeconds());
console.log(date.getHours());
console.log(date.toLocaleTimeString());
var d =val.timestamp;
var date=new Date(+d); //NB: use + before variable name
console.log(d);
console.log(date.toDateString());
console.log(date.getFullYear());
console.log(date.getMinutes());
console.log(date.getSeconds());
console.log(date.getHours());
console.log(date.toLocaleTimeString());
the methods above will generate this results
1541415288860
Mon Nov 05 2018
2018
54
48
13
1:54:48 PM
There's a bunch of methods that work perfectly with timestamps. Cant list them all

UNIX timestamp is number of seconds since 00:00:00 UTC on January 1, 1970 (according to Wikipedia).
Argument of Date object in Javascript is number of miliseconds since 00:00:00 UTC on January 1, 1970 (according to W3Schools Javascript documentation).
See code below for example:
function tm(unix_tm) {
var dt = new Date(unix_tm*1000);
document.writeln(dt.getHours() + '/' + dt.getMinutes() + '/' + dt.getSeconds() + ' -- ' + dt + '<br>');
}
tm(60);
tm(86400);
gives:
1/1/0 -- Thu Jan 01 1970 01:01:00 GMT+0100 (Central European Standard Time)
1/0/0 -- Fri Jan 02 1970 01:00:00 GMT+0100 (Central European Standard Time)

Using Moment.js, you can get time and date like this:
var dateTimeString = moment(1439198499).format("DD-MM-YYYY HH:mm:ss");
And you can get only time using this:
var timeString = moment(1439198499).format("HH:mm:ss");

The problem with the aforementioned solutions is, that if hour, minute or second, has only one digit (i.e. 0-9), the time would be wrong, e.g. it could be 2:3:9, but it should rather be 02:03:09.
According to this page it seems to be a better solution to use Date's "toLocaleTimeString" method.

Another way - from an ISO 8601 date.
var timestamp = 1293683278;
var date = new Date(timestamp * 1000);
var iso = date.toISOString().match(/(\d{2}:\d{2}:\d{2})/)
alert(iso[1]);

Based on #shomrat's answer, here is a snippet that automatically writes datetime like this (a bit similar to StackOverflow's date for answers: answered Nov 6 '16 at 11:51):
today, 11:23
or
yersterday, 11:23
or (if different but same year than today)
6 Nov, 11:23
or (if another year than today)
6 Nov 2016, 11:23
function timeConverter(t) {
var a = new Date(t * 1000);
var today = new Date();
var yesterday = new Date(Date.now() - 86400000);
var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
var year = a.getFullYear();
var month = months[a.getMonth()];
var date = a.getDate();
var hour = a.getHours();
var min = a.getMinutes();
if (a.setHours(0,0,0,0) == today.setHours(0,0,0,0))
return 'today, ' + hour + ':' + min;
else if (a.setHours(0,0,0,0) == yesterday.setHours(0,0,0,0))
return 'yesterday, ' + hour + ':' + min;
else if (year == today.getFullYear())
return date + ' ' + month + ', ' + hour + ':' + min;
else
return date + ' ' + month + ' ' + year + ', ' + hour + ':' + min;
}

function getTIMESTAMP() {
var date = new Date();
var year = date.getFullYear();
var month = ("0" + (date.getMonth() + 1)).substr(-2);
var day = ("0" + date.getDate()).substr(-2);
var hour = ("0" + date.getHours()).substr(-2);
var minutes = ("0" + date.getMinutes()).substr(-2);
var seconds = ("0" + date.getSeconds()).substr(-2);
return year + "-" + month + "-" + day + " " + hour + ":" + minutes + ":" + seconds;
}
//2016-01-14 02:40:01

The modern solution that doesn't need a 40 KB library:
Intl.DateTimeFormat is the non-culturally imperialistic way to format a date/time.
// Setup once
var options = {
//weekday: 'long',
//month: 'short',
//year: 'numeric',
//day: 'numeric',
hour: 'numeric',
minute: 'numeric',
second: 'numeric'
},
intlDate = new Intl.DateTimeFormat( undefined, options );
// Reusable formatter
var timeStamp = 1412743273;
console.log( intlDate.format( new Date( 1000 * timeStamp ) ) );

Pay attention to the zero problem with some of the answers. For example, the timestamp 1439329773 would be mistakenly converted to 12/08/2015 0:49.
I would suggest on using the following to overcome this issue:
var timestamp = 1439329773; // replace your timestamp
var date = new Date(timestamp * 1000);
var formattedDate = ('0' + date.getDate()).slice(-2) + '/' + ('0' + (date.getMonth() + 1)).slice(-2) + '/' + date.getFullYear() + ' ' + ('0' + date.getHours()).slice(-2) + ':' + ('0' + date.getMinutes()).slice(-2);
console.log(formattedDate);
Now results in:
12/08/2015 00:49

There are multiple ways to convert unix timestamp to time (HH/MM/SS)
Using new Date() - this is in-built in javascript
moment package - this is a famous node module, but this is going to deprecate.
dayjs package - this is one of the latest and fast growing node module
Using new Date()
const dateTimeStr = new Date(1504052527183).toLocaleString()
const result = (dateTimeStr.split(", ")[1]).split(":").join("/")
console.log(result)
Using moment
const moment = require('moment')
const timestampObj = moment.unix(1504052527183);
const result = timestampObj.format("HH/mm/ss")
console.log(result);
Using day.js
const dayjs = require('dayjs')
const result = dayjs(1504052527183).format("HH/mm/ss")
console.log(result);
you can check the timestamp to time conversion with an online time conversion tool

// Format value as two digits 0 => 00, 1 => 01
function twoDigits(value) {
if(value < 10) {
return '0' + value;
}
return value;
}
var date = new Date(unix_timestamp*1000);
// display in format HH:MM:SS
var formattedTime = twoDigits(date.getHours())
+ ':' + twoDigits(date.getMinutes())
+ ':' + twoDigits(date.getSeconds());

function getDateTimeFromTimestamp(unixTimeStamp) {
let date = new Date(unixTimeStamp);
return ('0' + date.getDate()).slice(-2) + '/' + ('0' + (date.getMonth() + 1)).slice(-2) + '/' + date.getFullYear() + ' ' + ('0' + date.getHours()).slice(-2) + ':' + ('0' + date.getMinutes()).slice(-2);
}
const myTime = getDateTimeFromTimestamp(1435986900000);
console.log(myTime); // output 01/05/2000 11:00

You can use the following function to convert your timestamp to HH:MM:SS format :
var convertTime = function(timestamp, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
var date = timestamp ? new Date(timestamp * 1000) : new Date();
return [
pad(date.getHours()),
pad(date.getMinutes()),
pad(date.getSeconds())
].join(typeof separator !== 'undefined' ? separator : ':' );
}
Without passing a separator, it uses : as the (default) separator :
time = convertTime(1061351153); // --> OUTPUT = 05:45:53
If you want to use / as a separator, just pass it as the second parameter:
time = convertTime(920535115, '/'); // --> OUTPUT = 09/11/55
Demo
var convertTime = function(timestamp, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
var date = timestamp ? new Date(timestamp * 1000) : new Date();
return [
pad(date.getHours()),
pad(date.getMinutes()),
pad(date.getSeconds())
].join(typeof separator !== 'undefined' ? separator : ':' );
}
document.body.innerHTML = '<pre>' + JSON.stringify({
920535115 : convertTime(920535115, '/'),
1061351153 : convertTime(1061351153, ':'),
1435651350 : convertTime(1435651350, '-'),
1487938926 : convertTime(1487938926),
1555135551 : convertTime(1555135551, '.')
}, null, '\t') + '</pre>';
See also this Fiddle.

function timeConverter(UNIX_timestamp){
var a = new Date(UNIX_timestamp*1000);
var hour = a.getUTCHours();
var min = a.getUTCMinutes();
var sec = a.getUTCSeconds();
var time = hour+':'+min+':'+sec ;
return time;
}

See Date/Epoch Converter.
You need to ParseInt, otherwise it wouldn't work:
if (!window.a)
window.a = new Date();
var mEpoch = parseInt(UNIX_timestamp);
if (mEpoch < 10000000000)
mEpoch *= 1000;
------
a.setTime(mEpoch);
var year = a.getFullYear();
...
return time;

Shortest
(new Date(ts*1000)+'').slice(16,24)
let ts = 1549312452;
let time = (new Date(ts*1000)+'').slice(16,24);
console.log(time);

Try this :
new Date(1638525320* 1e3).toISOString() //2021-12-03T09:55:20.000Z

function getDateTime(unixTimeStamp) {
var d = new Date(unixTimeStamp);
var h = (d.getHours().toString().length == 1) ? ('0' + d.getHours()) : d.getHours();
var m = (d.getMinutes().toString().length == 1) ? ('0' + d.getMinutes()) : d.getMinutes();
var s = (d.getSeconds().toString().length == 1) ? ('0' + d.getSeconds()) : d.getSeconds();
var time = h + '/' + m + '/' + s;
return time;
}
var myTime = getDateTime(1435986900000);
console.log(myTime); // output 01/15/00

moment.js
convert timestamps to date string in js
https://momentjs.com/
moment().format('YYYY-MM-DD hh:mm:ss');
// "2020-01-10 11:55:43"
moment(1578478211000).format('YYYY-MM-DD hh:mm:ss');
// "2020-01-08 06:10:11"

If you want to convert Unix time duration to real hours, minutes, and seconds, you could use the following code:
var hours = Math.floor(timestamp / 60 / 60);
var minutes = Math.floor((timestamp - hours * 60 * 60) / 60);
var seconds = Math.floor(timestamp - hours * 60 * 60 - minutes * 60 );
var duration = hours + ':' + minutes + ':' + seconds;

Code below also provides 3-digit millisecs, ideal for console log prefixes:
const timeStrGet = date => {
const milliSecsStr = date.getMilliseconds().toString().padStart(3, '0') ;
return `${date.toLocaleTimeString('it-US')}.${milliSecsStr}`;
};
setInterval(() => console.log(timeStrGet(new Date())), 299);

convert string to date and subtract X days

I need to make a function that takes a string and x number (subDays) of days as arguments and convert the string to a date and subtracts the x number of days from the date.
The input string is in format (YYYY-MM-DD) and I would like to get the same format back.
I get an Invalid Date error.
function newDate(date, subDays) {
var myDate = new Date(date);
myDate.setDate(myDate -subDays);
console.log("Date: " + myDate);
}

Here is one way you can do it
console.log( toYMD( subDays( '2016-12-11', 3) ) );
function subDays(date, days) {
var dateArray = date.split('-');
var myDate = new Date(dateArray[0], dateArray[1] - 1, dateArray[2]);
return new Date(myDate.setDate(myDate.getDate() - days));
}
function toYMD(d) {
return d.getFullYear() + "-" +
padZero(d.getMonth()+1) + "-" +
padZero(d.getDate());
}
function padZero(v) {
return (v < 10) ? "0" + v : v;
}

It is recommended not to use parser of Date constructor as it can be implementation dependant, other than some widely accepted formats. So parse the string ourselves.
Make adjustments to date by getting milliseconds with getTime and adding/subtracting milliseconds.
function newDate(date, subDays) {
function padZero(v) {
return (v < 10) ? "0" + v : v;
}
var dateArray = date.split('-').map(Number);
var myDate = new Date(dateArray[0], dateArray[1] - 1, dateArray[2]);
myDate = new Date(myDate.getTime() - subDays * 24 * 60 * 60 * 1000)
return myDate.getFullYear() + '-' + padZero(myDate.getMonth() + 1) + '-' + padZero(myDate.getDate());
}
console.log(newDate('2016-12-09', 8))
console.log(newDate('2016-12-09', 9))

First you have to specify what you are trying to deduct ; try this :-
function newDate(date, subDays) {
var myDate = new Date(date);
myDate.setDate(myDate.getDate() -subDays);
console.log("Date: " + myDate);
}

There is a package called datejs and you can easily use addDays(), addHours(), addMinutes() on a Date object. Here is the API doc: https://code.google.com/archive/p/datejs/wikis/APIDocumentation.wiki
function newDate(date, subDays) {
const d = Date.parse(date).addDays(-parseInt(subDays));
return `${d.getFullYear()}-${d.getMonth()}-${d.getDay()}`;
}

Make JavaScript Date function accept string or date object

I have this simple JavaScript function below that converts a JavaScript Date into a more readable format.
Right now you have to pass in a valid Date object but I would like to modify it so that it will accept a Date object or a string with a date value and return a formatted date regardless of which version is passed into it.
function formatDate(date) {
var hours = date.getHours();
var minutes = date.getMinutes();
var ampm = hours >= 12 ? 'pm' : 'am';
hours = hours % 12;
hours = hours ? hours : 12; // the hour '0' should be '12'
minutes = minutes < 10 ? '0'+minutes : minutes;
var strTime = hours + ':' + minutes + ' ' + ampm;
return date.getMonth()+1 + "/" + date.getDate() + "/" + date.getFullYear() + " " + strTime;
}
Usage:
var d = new Date(date_string);
var e = formatDate(d);
Converts this 2015-09-16 03:18:12 into 9/16/2015 3:18 pm
I want to be able to pass in a Date object...
var dateObject = new Date(date_string);
var e = formatDate(dateObject);
or a Date string...
var dateString = `2015-09-16 03:18:12`;
var e = formatDate(dateString);

The way to do this is to do type checking in the function via typeof.
function formatDate(date) {
if(typeof date === "string") {
// parse the date string into a Date object
}
// now date is already a Date object, or it has been parsed
var hours = date.getHours();
...
Actually parsing the Date string is outside the scope of the question.

You can check the type of variable before deciding which way to go:
function formatDate(date) {
if(typeof(date) == "string") {
var date_string = date;
date = new Date(date_string);
}
// Then just keep going!
}

Convert a Unix timestamp to time in JavaScript

I am storing time in a MySQL database as a Unix timestamp and that gets sent to some JavaScript code. How would I get just the time out of it?
For example, in HH/MM/SS format.

let unix_timestamp = 1549312452
// Create a new JavaScript Date object based on the timestamp
// multiplied by 1000 so that the argument is in milliseconds, not seconds.
var date = new Date(unix_timestamp * 1000);
// Hours part from the timestamp
var hours = date.getHours();
// Minutes part from the timestamp
var minutes = "0" + date.getMinutes();
// Seconds part from the timestamp
var seconds = "0" + date.getSeconds();
// Will display time in 10:30:23 format
var formattedTime = hours + ':' + minutes.substr(-2) + ':' + seconds.substr(-2);
console.log(formattedTime);
For more information regarding the Date object, please refer to MDN or the ECMAScript 5 specification.

function timeConverter(UNIX_timestamp){
var a = new Date(UNIX_timestamp * 1000);
var months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
var year = a.getFullYear();
var month = months[a.getMonth()];
var date = a.getDate();
var hour = a.getHours();
var min = a.getMinutes();
var sec = a.getSeconds();
var time = date + ' ' + month + ' ' + year + ' ' + hour + ':' + min + ':' + sec ;
return time;
}
console.log(timeConverter(0));

JavaScript works in milliseconds, so you'll first have to convert the UNIX timestamp from seconds to milliseconds.
var date = new Date(UNIX_Timestamp * 1000);
// Manipulate JavaScript Date object here...

Use:
var s = new Date(1504095567183).toLocaleDateString("en-US")
console.log(s)
// expected output "8/30/2017"
and for time:
var s = new Date(1504095567183).toLocaleTimeString("en-US")
console.log(s)
// expected output "3:19:27 PM"
see Date.prototype.toLocaleDateString()

Modern Solution (for 2020)
In the new world, we should be moving towards the standard Intl JavaScript object, that has a handy DateTimeFormat constructor with .format() method:
function format_time(s) {
const dtFormat = new Intl.DateTimeFormat('en-GB', {
timeStyle: 'medium',
timeZone: 'UTC'
});
return dtFormat.format(new Date(s * 1e3));
}
console.log( format_time(12345) ); // "03:25:45"
Eternal Solution
But to be 100% compatible with all legacy JavaScript engines, here is the shortest one-liner solution to format seconds as hh:mm:ss:
function format_time(s) {
return new Date(s * 1e3).toISOString().slice(-13, -5);
}
console.log( format_time(12345) ); // "03:25:45"
Method Date.prototype.toISOString() returns time in
simplified extended ISO 8601 format, which is always 24 or 27 characters long (i.e. YYYY-MM-DDTHH:mm:ss.sssZ or
±YYYYYY-MM-DDTHH:mm:ss.sssZ respectively). The timezone is always
zero UTC offset.
This solution does not require any third-party libraries and is supported in all browsers and JavaScript engines.

I'm partial to Jacob Wright's Date.format() library, which implements JavaScript date formatting in the style of PHP's date() function.
new Date(unix_timestamp * 1000).format('h:i:s')

I'd think about using a library like momentjs.com, that makes this really simple:
Based on a Unix timestamp:
var timestamp = moment.unix(1293683278);
console.log( timestamp.format("HH/mm/ss") );
Based on a MySQL date string:
var now = moment("2010-10-10 12:03:15");
console.log( now.format("HH/mm/ss") );

shortest one-liner solution to format seconds as hh:mm:ss: variant:
console.log(new Date(1549312452 * 1000).toISOString().slice(0, 19).replace('T', ' '));
// "2019-02-04 20:34:12"

In moment you must use unix timestamp:
const dateTimeString = moment.unix(1466760005).format("DD-MM-YYYY HH:mm:ss");

This works with PHP timestamps
var d = 1541415288860;
//var d =val.timestamp;
//NB: use + before variable name
var date = new Date(+d);
console.log(d);
console.log(date.toDateString());
console.log(date.getFullYear());
console.log(date.getMinutes());
console.log(date.getSeconds());
console.log(date.getHours());
console.log(date.toLocaleTimeString());
var d =val.timestamp;
var date=new Date(+d); //NB: use + before variable name
console.log(d);
console.log(date.toDateString());
console.log(date.getFullYear());
console.log(date.getMinutes());
console.log(date.getSeconds());
console.log(date.getHours());
console.log(date.toLocaleTimeString());
the methods above will generate this results
1541415288860
Mon Nov 05 2018
2018
54
48
13
1:54:48 PM
There's a bunch of methods that work perfectly with timestamps. Cant list them all

UNIX timestamp is number of seconds since 00:00:00 UTC on January 1, 1970 (according to Wikipedia).
Argument of Date object in Javascript is number of miliseconds since 00:00:00 UTC on January 1, 1970 (according to W3Schools Javascript documentation).
See code below for example:
function tm(unix_tm) {
var dt = new Date(unix_tm*1000);
document.writeln(dt.getHours() + '/' + dt.getMinutes() + '/' + dt.getSeconds() + ' -- ' + dt + '<br>');
}
tm(60);
tm(86400);
gives:
1/1/0 -- Thu Jan 01 1970 01:01:00 GMT+0100 (Central European Standard Time)
1/0/0 -- Fri Jan 02 1970 01:00:00 GMT+0100 (Central European Standard Time)

Using Moment.js, you can get time and date like this:
var dateTimeString = moment(1439198499).format("DD-MM-YYYY HH:mm:ss");
And you can get only time using this:
var timeString = moment(1439198499).format("HH:mm:ss");

The problem with the aforementioned solutions is, that if hour, minute or second, has only one digit (i.e. 0-9), the time would be wrong, e.g. it could be 2:3:9, but it should rather be 02:03:09.
According to this page it seems to be a better solution to use Date's "toLocaleTimeString" method.

Another way - from an ISO 8601 date.
var timestamp = 1293683278;
var date = new Date(timestamp * 1000);
var iso = date.toISOString().match(/(\d{2}:\d{2}:\d{2})/)
alert(iso[1]);

Based on #shomrat's answer, here is a snippet that automatically writes datetime like this (a bit similar to StackOverflow's date for answers: answered Nov 6 '16 at 11:51):
today, 11:23
or
yersterday, 11:23
or (if different but same year than today)
6 Nov, 11:23
or (if another year than today)
6 Nov 2016, 11:23
function timeConverter(t) {
var a = new Date(t * 1000);
var today = new Date();
var yesterday = new Date(Date.now() - 86400000);
var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
var year = a.getFullYear();
var month = months[a.getMonth()];
var date = a.getDate();
var hour = a.getHours();
var min = a.getMinutes();
if (a.setHours(0,0,0,0) == today.setHours(0,0,0,0))
return 'today, ' + hour + ':' + min;
else if (a.setHours(0,0,0,0) == yesterday.setHours(0,0,0,0))
return 'yesterday, ' + hour + ':' + min;
else if (year == today.getFullYear())
return date + ' ' + month + ', ' + hour + ':' + min;
else
return date + ' ' + month + ' ' + year + ', ' + hour + ':' + min;
}

function getTIMESTAMP() {
var date = new Date();
var year = date.getFullYear();
var month = ("0" + (date.getMonth() + 1)).substr(-2);
var day = ("0" + date.getDate()).substr(-2);
var hour = ("0" + date.getHours()).substr(-2);
var minutes = ("0" + date.getMinutes()).substr(-2);
var seconds = ("0" + date.getSeconds()).substr(-2);
return year + "-" + month + "-" + day + " " + hour + ":" + minutes + ":" + seconds;
}
//2016-01-14 02:40:01

The modern solution that doesn't need a 40 KB library:
Intl.DateTimeFormat is the non-culturally imperialistic way to format a date/time.
// Setup once
var options = {
//weekday: 'long',
//month: 'short',
//year: 'numeric',
//day: 'numeric',
hour: 'numeric',
minute: 'numeric',
second: 'numeric'
},
intlDate = new Intl.DateTimeFormat( undefined, options );
// Reusable formatter
var timeStamp = 1412743273;
console.log( intlDate.format( new Date( 1000 * timeStamp ) ) );

Pay attention to the zero problem with some of the answers. For example, the timestamp 1439329773 would be mistakenly converted to 12/08/2015 0:49.
I would suggest on using the following to overcome this issue:
var timestamp = 1439329773; // replace your timestamp
var date = new Date(timestamp * 1000);
var formattedDate = ('0' + date.getDate()).slice(-2) + '/' + ('0' + (date.getMonth() + 1)).slice(-2) + '/' + date.getFullYear() + ' ' + ('0' + date.getHours()).slice(-2) + ':' + ('0' + date.getMinutes()).slice(-2);
console.log(formattedDate);
Now results in:
12/08/2015 00:49

There are multiple ways to convert unix timestamp to time (HH/MM/SS)
Using new Date() - this is in-built in javascript
moment package - this is a famous node module, but this is going to deprecate.
dayjs package - this is one of the latest and fast growing node module
Using new Date()
const dateTimeStr = new Date(1504052527183).toLocaleString()
const result = (dateTimeStr.split(", ")[1]).split(":").join("/")
console.log(result)
Using moment
const moment = require('moment')
const timestampObj = moment.unix(1504052527183);
const result = timestampObj.format("HH/mm/ss")
console.log(result);
Using day.js
const dayjs = require('dayjs')
const result = dayjs(1504052527183).format("HH/mm/ss")
console.log(result);
you can check the timestamp to time conversion with an online time conversion tool

// Format value as two digits 0 => 00, 1 => 01
function twoDigits(value) {
if(value < 10) {
return '0' + value;
}
return value;
}
var date = new Date(unix_timestamp*1000);
// display in format HH:MM:SS
var formattedTime = twoDigits(date.getHours())
+ ':' + twoDigits(date.getMinutes())
+ ':' + twoDigits(date.getSeconds());

function getDateTimeFromTimestamp(unixTimeStamp) {
let date = new Date(unixTimeStamp);
return ('0' + date.getDate()).slice(-2) + '/' + ('0' + (date.getMonth() + 1)).slice(-2) + '/' + date.getFullYear() + ' ' + ('0' + date.getHours()).slice(-2) + ':' + ('0' + date.getMinutes()).slice(-2);
}
const myTime = getDateTimeFromTimestamp(1435986900000);
console.log(myTime); // output 01/05/2000 11:00

You can use the following function to convert your timestamp to HH:MM:SS format :
var convertTime = function(timestamp, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
var date = timestamp ? new Date(timestamp * 1000) : new Date();
return [
pad(date.getHours()),
pad(date.getMinutes()),
pad(date.getSeconds())
].join(typeof separator !== 'undefined' ? separator : ':' );
}
Without passing a separator, it uses : as the (default) separator :
time = convertTime(1061351153); // --> OUTPUT = 05:45:53
If you want to use / as a separator, just pass it as the second parameter:
time = convertTime(920535115, '/'); // --> OUTPUT = 09/11/55
Demo
var convertTime = function(timestamp, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
var date = timestamp ? new Date(timestamp * 1000) : new Date();
return [
pad(date.getHours()),
pad(date.getMinutes()),
pad(date.getSeconds())
].join(typeof separator !== 'undefined' ? separator : ':' );
}
document.body.innerHTML = '<pre>' + JSON.stringify({
920535115 : convertTime(920535115, '/'),
1061351153 : convertTime(1061351153, ':'),
1435651350 : convertTime(1435651350, '-'),
1487938926 : convertTime(1487938926),
1555135551 : convertTime(1555135551, '.')
}, null, '\t') + '</pre>';
See also this Fiddle.

function timeConverter(UNIX_timestamp){
var a = new Date(UNIX_timestamp*1000);
var hour = a.getUTCHours();
var min = a.getUTCMinutes();
var sec = a.getUTCSeconds();
var time = hour+':'+min+':'+sec ;
return time;
}

See Date/Epoch Converter.
You need to ParseInt, otherwise it wouldn't work:
if (!window.a)
window.a = new Date();
var mEpoch = parseInt(UNIX_timestamp);
if (mEpoch < 10000000000)
mEpoch *= 1000;
------
a.setTime(mEpoch);
var year = a.getFullYear();
...
return time;

Shortest
(new Date(ts*1000)+'').slice(16,24)
let ts = 1549312452;
let time = (new Date(ts*1000)+'').slice(16,24);
console.log(time);

Try this :
new Date(1638525320* 1e3).toISOString() //2021-12-03T09:55:20.000Z

function getDateTime(unixTimeStamp) {
var d = new Date(unixTimeStamp);
var h = (d.getHours().toString().length == 1) ? ('0' + d.getHours()) : d.getHours();
var m = (d.getMinutes().toString().length == 1) ? ('0' + d.getMinutes()) : d.getMinutes();
var s = (d.getSeconds().toString().length == 1) ? ('0' + d.getSeconds()) : d.getSeconds();
var time = h + '/' + m + '/' + s;
return time;
}
var myTime = getDateTime(1435986900000);
console.log(myTime); // output 01/15/00

moment.js
convert timestamps to date string in js
https://momentjs.com/
moment().format('YYYY-MM-DD hh:mm:ss');
// "2020-01-10 11:55:43"
moment(1578478211000).format('YYYY-MM-DD hh:mm:ss');
// "2020-01-08 06:10:11"

If you want to convert Unix time duration to real hours, minutes, and seconds, you could use the following code:
var hours = Math.floor(timestamp / 60 / 60);
var minutes = Math.floor((timestamp - hours * 60 * 60) / 60);
var seconds = Math.floor(timestamp - hours * 60 * 60 - minutes * 60 );
var duration = hours + ':' + minutes + ':' + seconds;

Code below also provides 3-digit millisecs, ideal for console log prefixes:
const timeStrGet = date => {
const milliSecsStr = date.getMilliseconds().toString().padStart(3, '0') ;
return `${date.toLocaleTimeString('it-US')}.${milliSecsStr}`;
};
setInterval(() => console.log(timeStrGet(new Date())), 299);