Parse Date Without Timezone JavaScript

Parse date without timezone javascript

The date is parsed correctly, it's just toString that converts it to your local timezone:

let s = "2005-07-08T11:22:33+0000";
let d = new Date(Date.parse(s));

// this logs for me 
// "Fri Jul 08 2005 13:22:33 GMT+0200 (Central European Summer Time)" 
// and something else for you

console.log(d.toString()) 

// this logs
// Fri, 08 Jul 2005 11:22:33 GMT
// for everyone

console.log(d.toUTCString())

Create a Date with a set timezone without using a string representation

using .setUTCHours() it would be possible to actually set dates in UTC-time, which would allow you to use UTC-times throughout the system.

You cannot set it using UTC in the constructor though, unless you specify a date-string.

Using new Date(Date.UTC(year, month, day, hour, minute, second)) you can create a Date-object from a specific UTC time.

How to ignore time-zone on new Date()?

As Frz Khan pointed, you can use the .toISOString() function when returning the date from your function, but if you're seeking the UTC format, use the .toUTCString(), it would output something like Mon, 18 Apr 2016 18:09:32 GMT

function updateLatestDate(sensorsData) {
    return new Date(Math.max.apply(null, sensorsData.map(function (e) {
        return new Date(e.MeasureDate).toUTCString();
    })));
}

Create a Date in js ignoring timezone

Yes! If you create all your Date objects using the Date.UTC function, then they will all be relative to the standard UTC timezone, even if the user's browser has a different timezone set.

For example:

var ex = new Date( Date.UTC( 2015, 3, 31 ) );

This will create a Date object for 3/31/2015 UTC and be consistent across all browsers regardless of their default timezone.

Internally, the date inside ex will still be converted in the user's local timezone. So if you read values from it, say the date, it will be relative to the user's browser time.

So if you need to read the time back out in UTC, you can do something like this:

ex.getUTCYear(); // 2015
ex.getUTCMonth(); // 3
ex.getUTCDate(); // 31

This will give you the value back in UTC time.

Avoid timezone correction for JavaScript Date

Values passed to the Date constructor are treated as local, toISOString uses UTC. Unfortunately ECMAScript doesn't have a timezone–free, date–only form.

If you want to use toISOString to format the timestamp, then one solution is to parse the values as UTC initially, e.g.

sendDate(d) {
    let date = new Date(Date.UTC(this.year, this.month, d));
    htmx.ajax("GET", "/some/url", { values: { "date": date.toISOString() } });
}

Example:

let d = new Date()
let year = d.getFullYear();
let month = d.getMonth()
let day = d.getDate();
let date = new Date(Date.UTC(year, month, day))
// Always shows the current local date as 00:00:00Z
console.log( date.toISOString() );

convert string to date without changing timezone in the string using java

Just omit the timezone format from the end of the String (letter Z).
For example, this will print Thu Nov 12 06:30:00 CET 2020

String s = "2020-11-12T6:30:00-0800";
DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss");
var date = format.parse(s);
System.out.println(date);

But if I add the letter Z at the end, it will interpret the given timezone and change time to my local timezone, when printed. So this will print Thu Nov 12 15:30:00 CET 2020

String s = "2020-11-12T6:30:00-0800";
DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ssZ");
var date = format.parse(s);
System.out.println(date);

More about the patterns can be found in the JavaDoc of SimpleDateFormat.

Javascript, Date.parse with no timezone

Date.parse returns the number of milliseconds since the epoch in UTC, so no matter what date/time string you pass in, you'll get UTC out. (See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/parse for more information.)

If you want to convert that to local time, you'll have to know your offset from UTC. You can get that from JavaScript thusly:

var offset = new Date().getTimezoneOffset()*60*1000;

(Date.prototype.getTimezoneOffset returns the offset in minutes, so we have to convert to milliseconds.)

Then you can construct your date with that offset:

var date = new Date(Date.parse("2014-06-01T00:00:00") + offset);

If you want to interpret that date as if it were in a different timezone, you would just use whatever millisecond offset is appropriate for that timezone. Keep in mind daylight savings, though: that will definitely complicate matters.

How to ignore user's time zone and force Date() use specific time zone

A Date object's underlying value is actually in UTC. To prove this, notice that if you type new Date(0) you'll see something like: Wed Dec 31 1969 16:00:00 GMT-0800 (PST). 0 is treated as 0 in GMT, but .toString() method shows the local time.

Big note, UTC stands for Universal time code. The current time right now in 2 different places is the same UTC, but the output can be formatted differently.

What we need here is some formatting

var _date = new Date(1270544790922); 
// outputs > "Tue Apr 06 2010 02:06:30 GMT-0700 (PDT)", for me
_date.toLocaleString('fi-FI', { timeZone: 'Europe/Helsinki' });
// outputs > "6.4.2010 klo 12.06.30"
_date.toLocaleString('en-US', { timeZone: 'Europe/Helsinki' });
// outputs > "4/6/2010, 12:06:30 PM"

This works but.... you can't really use any of the other date methods for your purposes since they describe the user's timezone. What you want is a date object that's related to the Helsinki timezone. Your options at this point are to use some 3rd party library (I recommend this), or hack-up the date object so you can use most of it's methods.

Option 1 - a 3rd party like moment-timezone

moment(1270544790922).tz('Europe/Helsinki').format('YYYY-MM-DD HH:mm:ss')
// outputs > 2010-04-06 12:06:30
moment(1270544790922).tz('Europe/Helsinki').hour()
// outputs > 12

This looks a lot more elegant than what we're about to do next.

Option 2 - Hack up the date object

var currentHelsinkiHoursOffset = 2; // sometimes it is 3
var date = new Date(1270544790922);
var helsenkiOffset = currentHelsinkiHoursOffset*60*60000;
var userOffset = _date.getTimezoneOffset()*60000; // [min*60000 = ms]
var helsenkiTime = new Date(date.getTime()+ helsenkiOffset + userOffset);
// Outputs > Tue Apr 06 2010 12:06:30 GMT-0700 (PDT)

It still thinks it's GMT-0700 (PDT), but if you don't stare too hard you may be able to mistake that for a date object that's useful for your purposes.

I conveniently skipped a part. You need to be able to define currentHelsinkiOffset. If you can use date.getTimezoneOffset() on the server side, or just use some if statements to describe when the time zone changes will occur, that should solve your problem.

Conclusion - I think especially for this purpose you should use a date library like moment-timezone.

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