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How to get hours in moment.js in GMT timezone?

For example if I do for the above date object something like: value.hours(), I get as output 16 instead of 18. I believe it returns the hours in the original GMT time, not like in my date object which is GMT+2. I can of course add 2 to the returned result, but it becomes cumbersome. Is there any way to get the hours correctly in my case?

I'm not sure as to what you've already tried, but I put the following into JSFiddle and it worked like a charm. I am currently in CST in America and it is 8:30 in the morning here. When I ran the snippet below I got today's date at 1:30 PM which I would assume is accurate in difference.
HTML
<div id="m1"></div>
JavaScript
var a = moment.tz(new Date(), "GMT");
document.getElementById('m1').innerHTML = a.format("YYYY MM DD; HH:mm");
The Moment.js documentation states the following in regards to creating a Moment object with a native JavaScript Date object:
You can create a Moment with a pre-existing native JavaScript Date object.
var day = new Date(2011, 9, 16);
var dayWrapper = moment(day);
This clones the Date object; further changes to the Date won't affect the Moment, and vice-versa.
To find the information quoted above quickly, when you reach the Moment.js documentation, it is located under the Parse section under sub-section Date.

To display local time:
value.local();
value.hours(); // 18
To reverse:
value.utc();
value.hours(); // 16

I think that you can solve it by doing what the docs says. Something like this:
moment().tz("America/Los_Angeles").format();
https://momentjs.com/timezone/docs/#/using-timezones/

can you get year/month/date from Date().getTime

I'm trying to figure out what the best way to store date in DB is. Using
new Date().getTime()
seems to be the most common but is it possible to get the year/month/date from the timestamp? or is getTime meant as a way to sort data. Should I just store new Date() directly if I want retrieve the y/m/d information again?
Thanks

var dateObject = new Date();
var year = dateObject.getYear();
var month = dateObject.getMonth();
var date = dateObject.getDate();

getTime() is useful for saving in files and databases because it represents the date and time as a single number, which is very compact. It's also represented in UTC, so the timezone doesn't matter.
You can convert it back to a Date with:
var thatTime = Date(retrievedTime);
Then you can use thatTime.getYear(), thatTime.getMonth(), etc. to extract parts of the saved time.

#Barmar is absolutely correct. However, if you want the year, month and date information stored in an easily readable way, you can go two ways (assuming you only want the date and not the time):
Use the Date object's getYear, getMonth and getDate methods respectively and store them in separate fields (less processing for display and you can choose which parts you want, but more parsing required for sorting, etc.)
toDateString (and toLocaleString for non-American-English and flexibility) gives a human-readable string like "Wed Jul 28 1993" (and then you'd slice off the first 4 characters).

Moment.js transform to date object

Using Moment.js I can't transform a correct moment object to a date object with timezones. I can't get the correct date.
Example:
var oldDate = new Date(),
momentObj = moment(oldDate).tz("MST7MDT"),
newDate = momentObj.toDate();
console.log("start date " + oldDate)
console.log("Format from moment with offset " + momentObj.format())
console.log("Format from moment without offset " + momentObj.utc().format())
console.log("(Date object) Time with offset " + newDate)
console.log("(Date object) Time without offset "+ moment.utc(newDate).toDate())

Use this to transform a moment object into a date object:
From http://momentjs.com/docs/#/displaying/as-javascript-date/
moment().toDate();
Yields:
Tue Nov 04 2014 14:04:01 GMT-0600 (CST)

As long as you have initialized moment-timezone with the data for the zones you want, your code works as expected.
You are correctly converting the moment to the time zone, which is reflected in the second line of output from momentObj.format().
Switching to UTC doesn't just drop the offset, it changes back to the UTC time zone. If you're going to do that, you don't need the original .tz() call at all. You could just do moment.utc().
Perhaps you are just trying to change the output format string? If so, just specify the parameters you want to the format method:
momentObj.format("YYYY-MM-DD HH:mm:ss")
Regarding the last to lines of your code - when you go back to a Date object using toDate(), you are giving up the behavior of moment.js and going back to JavaScript's behavior. A JavaScript Date object will always be printed in the local time zone of the computer it's running on. There's nothing moment.js can do about that.
A couple of other little things:
While the moment constructor can take a Date, it is usually best to not use one. For "now", don't use moment(new Date()). Instead, just use moment(). Both will work but it's unnecessarily redundant. If you are parsing from a string, pass that string directly into moment. Don't try to parse it to a Date first. You will find moment's parser to be much more reliable.
Time Zones like MST7MDT are there for backwards compatibility reasons. They stem from POSIX style time zones, and only a few of them are in the TZDB data. Unless absolutely necessary, you should use a key such as America/Denver.

.toDate did not really work for me, So, Here is what i did :
futureStartAtDate = new Date(moment().locale("en").add(1, 'd').format("MMM DD, YYYY HH:MM"))
hope this helps

Since momentjs has no control over javascript date object I found a work around to this.
const currentTime = new Date();
const convertTime = moment(currentTime).tz(timezone).format("YYYY-MM-DD HH:mm:ss");
const convertTimeObject = new Date(convertTime);
This will give you a javascript date object with the converted time

The question is a little obscure. I ll do my best to explain this. First you should understand how to use moment-timezone. According to this answer here TypeError: moment().tz is not a function, you have to import moment from moment-timezone instead of the default moment (ofcourse you will have to npm install moment-timezone first!). For the sake of clarity,
const moment=require('moment-timezone')//import from moment-timezone
Now in order to use the timezone feature, use moment.tz("date_string/moment()","time_zone") (visit https://momentjs.com/timezone/ for more details). This function will return a moment object with a particular time zone. For the sake of clarity,
var newYork= moment.tz("2014-06-01 12:00", "America/New_York");/*this code will consider NewYork as the timezone.*/
Now when you try to convert newYork (the moment object) with moment's toDate() (ISO 8601 format conversion) you will get the time of Greenwich,UK. For more details, go through this article https://www.nhc.noaa.gov/aboututc.shtml, about UTC. However if you just want your local time in this format (New York time, according to this example), just add the method .utc(true) ,with the arg true, to your moment object. For the sake of clarity,
newYork.toDate()//will give you the Greenwich ,UK, time.
newYork.utc(true).toDate()//will give you the local time. according to the moment.tz method arg we specified above, it is 12:00.you can ofcourse change this by using moment()
In short, moment.tz considers the time zone you specify and compares your local time with the time in Greenwich to give you a result. I hope this was useful.

To convert any date, for example utc:
moment( moment().utc().format( "YYYY-MM-DD HH:mm:ss" )).toDate()

let dateVar = moment('any date value');
let newDateVar = dateVar.utc().format();
nice and clean!!!!

I needed to have timezone information in my date string. I was originally using moment.tz(dateStr, 'America/New_York').toString(); but then I started getting errors about feeding that string back into moment.
I tried the moment.tz(dateStr, 'America/New_York').toDate(); but then I lost timezone information which I needed.
The only solution that returned a usable date string with timezone that could be fed back into moment was moment.tz(dateStr, 'America/New_York').format();

try (without format step)
new Date(moment())
var d = moment.tz("2019-04-15 12:00", "America/New_York");
console.log( new Date(d) );
console.log( new Date(moment()) );
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.23/moment-timezone-with-data.min.js"></script>

moment has updated the js lib as of 06/2018.
var newYork = moment.tz("2014-06-01 12:00", "America/New_York");
var losAngeles = newYork.clone().tz("America/Los_Angeles");
var london = newYork.clone().tz("Europe/London");
newYork.format(); // 2014-06-01T12:00:00-04:00
losAngeles.format(); // 2014-06-01T09:00:00-07:00
london.format(); // 2014-06-01T17:00:00+01:00
if you have freedom to use Angular5+, then better use datePipe feature there than the timezone function here. I have to use moment.js because my project limits to Angular2 only.

new Date(moment()) - could give error while exporting the data column in excel
use
moment.toDate() - doesn't give error or make exported file corrupt

How to get difference of saved time and current time in jquery?

I want to get the time difference between saved time and current time in javascript or jquery. My saved time looks like Sun Oct 24 15:55:56 GMT+05:30 2010.
The date format code in java looks like
String newDate = "2010/10/24 15:55:56";
DateFormat format = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = format.parse(newDate);
How to compare it with the current time and get the difference?
Is there any inbuilt function in jquery or javascript??
Any suggestions or links would be appreciative!!!
Thanks in Advance!
Update
Date is stored as varchar in the DB. I am retriving it to a String variable and then change it to java.util.Date object. The java code looks like
String newDate = "2010/10/24 15:55:56";
DateFormat format = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = format.parse(newDate);
This date object was sent to client. There i want to compare the saved date with current date and want to show the time difference like 2 secs ago, 2 hours ago, 2 days ago etc... like exactly in facebook. I have gone through some date to timestamp conversion tutorial in java script and now i can get the difference in timestamp. Now, i want to know how i shall change it to some format like "2 secs or 2 days or 24 hours"??. Or, how i shall change it back to date format???

Convert them into timestamps which are actually integers and can get subtracted from each other. The you just have to convert back the resulting timestamp to a javascript date object.
var diff = new Date();
diff.setTime( time2.getTime()-time1.getTime() );

You dont need to explicit convert, just do this:
var timediff = new Date() - savedTime;
This will return the difference in milliseconds.

jQuery doesn't add anything for working with dates. I'd recommend using Datejs in the event that the standard JavaScript Date API isn't sufficient.
Perhaps you could clarify exactly what input and output you're aiming for. What do you mean by "the difference?" There is more than one way to express the difference between to instants in time (primarily units and output string formatting).
Edit: since you said you're working with jQuery, how about using CuteTime? (Demo page)

Java date format to JavaScript date format

I would like to be able to convert a Java date format string, e.g. dd/MM/yyyy (07/06/2009) to a JavaScript date format string, e.g. dd/mm/yy (07/06/2009).
Has anyone done this before, or got any idea where I might find some code that already does this?
Edit:
Thanks for all the replies but now I realize my mistake and possibly why so many of you were struggling to understand the question; JavaScript doesn't have a built in date formatting ability. I am using the jQuery UI datepicker and I have been setting its date format, assuming it would be calling a standard JS function at some point, not using its own library! When I googled for formatting strings I jumped straight to the tables of what letters could be used, skipping the bit at the beginning explaining how to use the script.
Anyway I'll have to go ahead and possibly write my own I guess, converting a Java date format string into a jQuery date format string (or as close as possible) - I am working on the i18n of our product and have created a java class that stores the preferred date format string used throughout the application, my intention was to also have the ability to supply any jsps with the format string that is equivalent in JS.
Thanks anyway.

If you just need to pass a date from Java to JavaScript, the best way to do it, I think, would be to convert the Java date to milliseconds using date.getTime(), create a JavaScript date initialized with this milliseconds value with new Date(milliseconds)and then format the date with the means of the JavaScript Date object, like: date.toLocaleString().

You could use my plugin jquery-dateFormat.
// Text
$.format.date("2009-12-18 10:54:50.546", "dd/MM/yyyy");
// HTML Object
$.format.date($("#spanDate").text(), "dd/MM/yyyy");
// Scriptlet
$.format.date("<%=java.util.Date().toString()%>", "dd/MM/yyyy");
// JSON
var obj = ajaxRequest();
$.format.date(obj.date, "dd/MM/yyyy");

A similar topic has been answered here:
Converting dates in JavaScript
I personally have found this to be a rather large pain and took the author's suggestion and used a library. As noted, jQuery datepicker has one that is a viable solution if you can afford the overhead of download for your application or already using it.

Check out moment.js! It's "A lightweight javascript date library for parsing, manipulating, and formatting dates". It is a really powerful little library.
Here's an example...
var today = moment(new Date());
today.format("MMMM D, YYYY h:m A"); // outputs "April 11, 2012 2:32 PM"
// in one line...
moment().format("MMMM D, YYYY h:m A"); // outputs "April 11, 2012 2:32 PM"
Here's another example...
var a = moment([2012, 2, 12, 15, 25, 50, 125]);
a.format("dddd, MMMM Do YYYY, h:mm:ss a"); // "Monday, March 12th 2012, 3:25:50 pm"
a.format("ddd, hA"); // "Mon, 3PM"
a.format("D/M/YYYY"); // "12/3/2012"
Also, its worth mentioning to checkout date.js. I think the two libraries complement each other.

This JavaScript library should be able to help you.
http://plugins.jquery.com/project/fIsForFormat
(I don't know why they have it as a jQuery Plugin, because it works standalone.)
You'd simply split the original formatted date into its individual elements and then create a new Date Object with those elements. Then, use this library's "Date.f()" method to output it into any format you could want.
For example:
var dateOld = "11/27/2010",
dateArr = date1.split("/"),
dateObj = new Date(dateArr[2], dateArr[0], dateArr[1]),
dateNew = dateObj.f("MMM d, yyyy");
document.write("Old Format: " + dateOld + "<br/>New Format: " + dateNew);

This works fine for me:
<%
Date date = Calendar.getInstance().getTime();
%>
<script>
var d = new Date(<%=date.getTime()%>);
alert(d);
</script>

I suggest you the MomentJS with this Plugin that allow you to convert a Java pattern to a JS pattern (MomentJS)

On Java Side
I recommend passing an Instant string which conforms to ISO 8601 standard.
import java.time.Instant;
class Main {
public static void main(String[] args) {
Instant instant = Instant.now();
// You can pass the following string to JavaScript
String strInstant = instant.toString();
System.out.println(strInstant);
// If the number of milliseconds from epoch is required
long millis = instant.toEpochMilli();
System.out.println(millis);
}
}
Output from a sample run:
2022-12-31T09:40:52.280726Z
1672479652280
ONLINE DEMO
Learn more about the modern Date-Time API from Trail: Date Time.
On JavaScript Side
Now, you can parse the ISO 8601 string on the JavaScript side simply by passing it as a parameter to Date constructor. You can also instantiate the Date object with the number of milliseconds from the epoch.
var date = new Date("2022-12-31T09:40:52.280726Z");
console.log(date.toISOString());
// Or if the number of milliseconds from epoch has been received
date = new Date(1672479652280);
console.log(date.toISOString());

The javascript code in this page implements some date functions and they "use the same format strings as the java.text.SimpleDateFormat class, with a few minor exceptions". It is not the very same as you want but it can be a good start point.

If you just want to format dates my date extensions will do that well - it also parses data formats and does a lot of date math/compares as well:
DP_DateExtensions Library
Not sure if it'll help, but I've found it invaluable in several projects.

If you are using java, take a look at the Simple Date Format class.