Format date time JavaScript - javascript

How to format date and time like this in JavaScript ?
March 05, 2012 # 14:30 (UTC - 9:30)
I use this code to calculate EST time :
function getDate() {
var now = new Date();
var utc = now.getTime() + (now.getTimezoneOffset() * 60000);
return new Date(utc + (3600000 * -4));
}

I use the date-time-format that Tats recommended because doing it manually is a huge PIA.
var yourDate = dateFormat(getDate(), "mmmm dd, yyyy # HH:MM) + "(UTC -9:30)";
Keep in mind this isn't Daylight Savings aware.. and you are asking for UTC -9:30 in your format, but your function converts to -4. Also, I believe that now.getTime returns in UTC.. so you can just add your difference there.
JavaScript Date Format

Check out date.js! It's a really powerful little library for working with Dates in JavaScript.
To get today's date in EST, you can do something like...
var today = new Date();
today.toString(); // outputs "Wed Apr 11 2012 15:40:40 GMT-0500 (CDT)"
today.setTimezone("EST");
today.toString(); // outputs "Wed Apr 11 2012 14:40:40 GMT-0500 (CDT)"
Also, its worth mentioning to checkout moment.js. I think the two libraries complement each other.

If you do just
var now = new Date();
document.write(now);
you will get
Wed Mar 14 2012 20:53:06 GMT+0000 (GMT Standard Time)
Link1, Link2.
Is it what you want?

Related

Having issue calculating timeSince due to timeZone confusion

So I am a little bit confused. the server return date is in UTC ISO format, my local time is CST.
so I use toLocaleString() and then subtract the difference but I get a negative number. I rather use react native library rather than installing new libraries such as moment
export function timeSince(date) {
//date is 2022-11-07T18:36:39.543 which is UTC, not CST
date = date.toLocaleString("en-US", {
timeZone: "CST",
});
// somehow stayed 2022-11-07T18:36:39.543
date = new Date(date);
//Mon Nov 07 2022 18:36:39 GMT-0600 (Central Standard Time)
Mon Nov 07 2022 12:29:21 GMT-0600 (Central Standard Time)
'2022-11-07T18:27:38.03'
var seconds = Math.floor((new Date() - date) / 1000); // -21506
return seconds
}

javascript similar Date objects, return defferent epochs?

when i use different Date constructors i receive similar Date objects but when i get there epoch values they have slightly different values.
Is it a bug or something or i'm just passing wrong value formats into constructors?
> date1 = new Date();
Sun Oct 04 2015 15:31:33 GMT+0330 (IRST)
> date2 = new Date(date1.toString());
Sun Oct 04 2015 15:31:33 GMT+0330 (IRST)
> date3 = new Date(date1.toISOString());
Sun Oct 04 2015 15:31:33 GMT+0330 (IRST)
> date1.getTime();
1443960093117
> date2.getTime();
1443960093000
> date3.getTime();
1443960093117
I'm using node(v0.12.2) in Ubuntu 14.04.1.
Apparently date1.toString() does not take the milliseconds into account while date1.toISOString() does. Yes, this is not a bug, you're just passing different strings. For me:
var date1 = new Date();
console.log(date1.toString(), date1.toISOString())
// Sun Oct 04 2015 14:54:37 GMT+0200
// 2015-10-04T12:54:37.113Z
The ISO date format includes a field to represent a fractional part of a second. The default date format doesn't, and when a default date format is parsed the system assumes the second value is exact.
> new Date().toString()
'Sun Oct 04 2015 07:53:48 GMT-0500 (CDT)'
> new Date().toISOString()
'2015-10-04T12:53:58.769Z'
In the ISO string, .769 is the seconds fraction part.
When you just log a date it automatically uses the default method .toString() version which drops the milliseconds. Using the below code you can see that the .###Z is dropped for .toString() but not for .toISOString() because it is in the extended ISO format.
var date1 = new Date();
var date2 = new Date(date1.toString());
var date3 = new Date(date1.toISOString());
console.log('date1 ' + date1.toISOString());
console.log('date2 ' + date2.toISOString());
console.log('date3 ' + date3.toISOString());
console.log('date1 ' + date1.getTime());
console.log('date2 ' + date2.getTime());
console.log('date3 ' + date3.getTime());
Which returns
date1 2015-10-04T13:34:37.778Z
date2 2015-10-04T13:34:37.000Z
date3 2015-10-04T13:34:37.778Z
date1 1443965677778
date2 1443965677000
date3 1443965677778
Hopefully this helps.

Remove time from GMT time format

I am getting a date that comes in GMT format, Fri, 18 Oct 2013 11:38:23 GMT. The problem is that the time is messing up the timeline that I am using.
How can I strip out everything except for the actual date?
If you want to keep using Date and not String you could do this:
var d=new Date(); //your date object
console.log(new Date(d.setHours(0,0,0,0)));
-PS, you don't need a new Date object, it's just an example in case you want to log it to the console.
http://www.w3schools.com/jsref/jsref_sethours.asp
Like this:
var dateString = 'Mon Jan 12 00:00:00 GMT 2015';
dateString = new Date(dateString).toUTCString();
dateString = dateString.split(' ').slice(0, 4).join(' ');
console.log(dateString);
I'm using this workaround :
// d being your current date with wrong times
new Date(d.getFullYear(), d.getMonth(), d.getDate())
You could use Moment.js, a library that provides many helper functions to validate, manipulate, display and format dates and times in JavaScript.
Using Moment.js lib:
var dateString = new Date('Mon Jan 12 00:00:00 GMT 2015');
moment(dateString).format('YYYY-MM-DD HH:mm');
Or simplified:
moment('Mon Jan 12 00:00:00 GMT 2015').format('YYYY-MM-DD HH:mm')
Well,
Here is my Solution
let dateString = 'Mon May 25 01:07:00 GMT 2020';
let dateObj = new Date(dateString);
console.log(dateObj.toDateString());
// outputs Mon May 25 2020
See its documentation on MDN https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toDateString
Just cut it with substring:
var str = 'Fri, 18 Oct 2013 11:38:23 GMT';
str = str.substring(0,tomorrow.toLocaleString().indexOf(':')-3);
In this case you can just manipulate your string without the use of a Date object.
var dateTime = 'Fri, 18 Oct 2013 11:38:23 GMT',
date = dateTime.split(' ', 4).join(' ');
document.body.appendChild(document.createTextNode(date));
You can first convert the date to String:
String dateString = String.valueOf(date);
Then apply substring to the String:
dateString.substring(4, 11) + dateString.substring(30);
You need to take care as converting date to String will actually change the date format as well.

How to Convert Hard Coded date into standard GMT format

I need to convert a hard coded date into a standard GMT format.How can I do this?
The date I have is in the following format:
var myDate = 'dd|mm|yyyy';
There is no time or day description in the date.Just the 'dd|mm|yyyy' string.
Is there a way I can convert it into GMT?
Thanks in advance.
a = '22/02/2014'.split('/')
d = new Date(a[2],parseInt(a[1], 10) - 1,a[0])
//Sat Feb 22 2014 00:00:00 GMT+0530 (India Standard Time)
Now you have a javascript date object in d
utc = d.getUTCDate() + "/" + (d.getUTCMonth() + 1 ) + "/" + d.getUTCFullYear();
//"21/2/2014" for an accurate conversion to UTC time of day is a must.
If you are in say India, the Javascript Date object will have timeZoneOffset 330. So its not possible to keep a javascript Date object with timezone GMT unless your system time is GMT.
So if you want a Date object for calculation, you can create one with localTimezone and simply suppose it is GMT
pseudoGMT = new Date( Date.parse(d) + d.getTimezoneOffset() * 60 * 1000);
//Fri Feb 21 2014 18:30:00 GMT+0530 (India Standard Time)
If you can explain your high level requirement we might be able to help with some alternate solutions.
Use regex matching to extract the data you need:
var myDate = "21|01|2014";
var data = myDate.match(/(\d{2})\|(\d{2})\|(\d{4})/);
var date = new Date(data[3], data[2] - 1, data[1]);
Note that the month is 0-indexed, so january = 0
More on regular expressions: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp

Convert date to end of day

I get time in milliseconds from the server. I convert it to Date and get -
Mon Jul 22 2013 11:16:01 GMT+0200 (W. Europe Daylight Time) as the date in the record.
I want to separate out data of Monday, Tuesday etc into arrays. I am thinking of converting this date to Mon Jul 22 2013 23:59:59 GMT+0200 (W. Europe Daylight Time) and then filter out the records.
How can i change the date to the required end of the day time? or is there an easier way to do this ?
You could always construct a new DateTime object just using the year, month and day properties from the existing date, like so:
var actualDate = new Date(); // 2013-07-30 17:11:00
var endOfDayDate = new Date(actualDate.getFullYear()
,actualDate.getMonth()
,actualDate.getDate()
,23,59,59); // 2013-07-30 23:59:59
For future visitors, just use
var start = new Date();
var end = new Date();
start.setHours(0,0,0,0);
end.setHours(23,59,59,999);
Using http://momentjs.com:
var now = new Date().getTime();
var endOfDay = moment(now).endOf("day").toDate(); // Wed Jan 20 2016 23:59:59 GMT-0800 (PST)
var actualDate = new Date()
var eodDate = new Date(Math.floor(actualDate.getTime()/86400000+1)*86400000 + actualDate .getTimezoneOffset()*60000 - 1000)
where 86400000 are total milliseconds in a day
If two Date Objects are on the same day then they have the same Date String:
new Date('1374488161000').toDateString()
=> "Tue Jul 30 2013"
new Date('13744917610403').toDateString()
=> "Tue Jul 30 2013"
Although a rather naive method of comparing days, it's probably the simplest comparison.

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