Develop Reference

Javascript, trying to get date part time only

I have a date field coming from SQL as follows:
2022-06-30T00:00:00.000Z
Im trying to get the first 10 characters (date in format yyyy-mm-dd) from it, but I can't get it to work.
First, I tried a "left" function
textPaidThru= pt.slice(0,10)
And I got
Wed Jun 29
Then I tried moment
let textPaidThru = moment(paidThru).format('YYYY-MM-DD');
But Im getting this:
2022-06-29
No matter which method I try to use, I always get the provided date minus one day.
I encounter working with dates very hard in JS. Is there a way to get the date part only as provided by SQL? This is the value Im expecting:
2022-06-30
Thanks.

TL;DR; Timezones
Actual Answer
You could just use some vanilla javascript and parse it like this:
Note month is zero index in Date, so you will need to add 1 to each:
const dateToParse = "2022-06-30T00:00:00.000Z"
let parsedDate = new Date(dateToParse)
const formattedDate = `${parsedDate.getFullYear()}-${parsedDate.getMonth()+1}-${parsedDate.getDate()}`
console.log(formattedDate)
The reason you are getting 6-29 is most likely due to you not living in UTC+0. I get 6-29 as well, but that is because I live in UTC-7.
If you look in the code below I change the time to be UTC-7 (which should work for your timezone as well if what your profile says is correct UTC-3) and the console log for me displays 6-30 now.
const dateToParse = "2022-06-30T07:00:00.000Z"
let parsedDate = new Date(dateToParse)
const formattedDate = `${parsedDate.getFullYear()}-${parsedDate.getMonth()+1}-${parsedDate.getDate()}`
console.log(formattedDate)

If you know you'll always get the same format (well, you probably will), you can just use split, something like.
let dateTime = '2022-03-25T02:03:04.000Z';
let onlyDate = date.split('T')[0];
This will split the string at T and you basically only want the first part (array index 0) and that's it.

Date(string) shows different date and time using toLocaleString

I want to turn the string 1822-01-01 00:00:00 into a date by:
var d= new Date("1822-01-01 00:00:00");
What I expect using d.toLocaleString() is 1.1.1822, 00:00:00, but what I get is 31.12.1821, 23:53:28.
See fiddle: https://jsfiddle.net/f1kLpfgd/
Javascript Date string constructing wrong date explains the wrong date with time zones. I have a different problem, as even minutes and seconds differ from my input. The solution using the new Date(1822, 0, 1, 0, 0, 0, 0) constructor does not work for me, as the result is 31.12.1821, 23:53:28.
Is it because the year is before 1901? But even 1899 works perfectly fine...
Update
For the formatting example custom VS toLocaleString, see updated fiddle: https://jsfiddle.net/f1kLpfgd/8/

If you don't want to use some library like date-fns , moment.js ...
To get the desired you could try like:
var dateString = "1822-01-01 00:00:00";
var d = new Date(dateString);
var formatted = d.getDate() +'.'+
(d.getMonth()+1) +'.'+
d.getFullYear() +', '+
dateString.substr(11);
console.log(formatted);

I want to turn the string 1822-01-01 00:00:00 into a date by:
var d= new Date("1822-01-01 00:00:00");
What I expect using d.toLocaleString() is 1.1.1822, 00:00:00, but what I get is 31.12.1821, 23:53:28.
Do not use the built-in parser for non-standard strings as whatever you get is implementation dependent and likely not what you expect in at least some hosts. In Safari, d will be an invalid date.
The format returned by toLocaleString is implementation dependent and varies between browsers. For me, new Date().toLocaleString() returns "9/21/2017, 9:48:49 AM", which is not consistent with the format typically used either in my locality or by users of the language I speak.
If you just want to reformat the string, see Reformat string containing date with Javascript.
If you want to know how to parse the string correctly, see Why does Date.parse
give incorrect results?
If you want to format a Date, see Where can I find documentation on formatting a date in JavaScript?

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

javascript : how to get 'utc date'

I have a date in this string format "02/28/2012" and I want to convert it to UTC.
I'm using the jquery datepicker to select thedate and populate an inputbox. any clues?
Thanks

var datestr = "07/08/2005";
var datearr = datestr.split("/")
var utc = Date.UTC(datearr[2],datearr[0],datearr[1]);

var utcdate = Date.UTC(2012,2,28);

The other answers are good, but they will give you the wrong result.
In Javascript, the month argument is zero-indexed, so make sure to subtract 1 from the standard month number,
var utcms = Date.UTC(2012,2-1,28);
Unfortunately jquery .datepicker.parseDate(str) injects a local timezone (it would be nice if the documentation said this), and Date(str) and Date.parse(str) appear unpredictable about their treatment of local vs UTC.

Is there a simple conversion for this datetime format?

I'm retrieving data from a JSON feed using jQuery and as part of the feed I'm getting 'datetime' attributes like "2009-07-01 07:30:09". I want to put this information into a javascript Date object for easy use but I don't believe the Date object would recognize this kind of format if I simply plugged it into the constructor. Is there a function or maybe a clever trick I can use to quickly break down this format into something the Date object can recognize and use?

The "date" attribute you are retrieving from that webservice is not a real Date, as it is not a recognized date format.
The easiest way to handle it as a Date object would be to replace the empty space with a "T":
var receivedDate = "2009-07-01 07:30:09";
var serializedDate = new Date(receivedDate.replace(" ", "T"));
alert(serializedDate);
This is not the most correct, as it is not handling timezones, but in most cases will work.

See this and this.
input = "2009-07-01 07:30:09";
var res = input.match(/([\d\-]+) (\d+):(\d+):(\d+)/);
date = new Date(Date.parse(res[1]));
date.setHours(res[2]);
date.setMinutes(res[3]);
date.setSeconds(res[4]);
console.log(date);
Edit: My original answer was
t = new Date(Date.parse("2009-07-01 07:30:09"));
which did not throw any error in chrome but all the same incorrectly parsed the date. This threw me off. Date.parse indeed appears to be quite flaky and parsing the complete date and time with it is probably not very reliable.
Edit2: DateJS appears to be a good solution for when some serious parsing of text to date is needed but at 25 kb it is a bit heavy for casual use.

var str="2009-07-01 07:30:09";
It depends on the time zone,
and if the date string has subtracted 1 for the month.
If it is GMT time, and the 07 means July and not August:
var str="2009-07-01 07:30:09";
var d=new Date(), time;
str=str.split(/\D0?/);
str[1]-=1;
time=str.splice(3);
d.setUTCFullYear.apply(d,str);
d.setUTCHours.apply(d,time)
alert(d)
/* returned value: (Date)
Wed Jul 01 2009 03:30:09 GMT-0400 (Eastern Daylight Time) or local equivilent
*/

This may be a bit cumbersome, but the JavaScript Date object will take an argument list of YYYY,MM,DD,HH,MM,SS. Parse out the date value and pass it to a Date constructor, e.g.
var splitDT= '2009-07-01 07:30:09'.split(' '); // ['2009-07-01','07:30:09']
var d= splitDT[0].split('-');
var t= splitDT[1].split(':');
alert( (new Date(d[0],d[1],d[2],t[0],t[1],t[2])) );
Bah. Had to use the array index values instead. Yeah, that's a mess. But it works.