Develop Reference

Kind of time (yyyymmddThhmmZ)

I'm trying to generate links to Google calendar and see this tool:
https://decomaan.github.io/google-calendar-link-generator/
And the links are generated as:
https://www.google.com/calendar/render?action=TEMPLATE&text=Appointment+with+VULKOVICH%2C+BILL&details=a+Description&location=a+Location&dates=20210105T103300Z%2F20210114T103300Z
and as you can see the dates are like:
20210105T103300Z
and I am trying to convert this to my own dates but I don't know which type is this and how to format. I have the dates both, in moment or in date, but don't know how to convert.

That's ISO-8601
The first part is the date in year-month-date order, the second part is the time and the final letter indicates the timezone (here Z for 'Zulu')

Since you're using moment.js: moment().utc().format('YYYYMMDDTHHmmss[Z]'), or without a library new Date().toISOString().replace(/\W/g,'').replace(/\d{3}Z/,'Z'). This is really a duplicate of How to format a JavaScript date.
Source: comment by RobG Jan 11 at 12:58

Change moment timezone not reflecting to .toDate()

Ngx Bootstrap Datepicker returns a JS Date object.
I have a custom Time picker that returns a string formatted as HH:mm.
What I need to do right now is to create a JS Date object with the selected Date, selected Time and a specific TimeZone.
I'm trying to use moment (cause we use that for dates in the whole application) but I'm having not expected behaviours.
I'm trying to:
const specificMoment = moment.tz(date, timeZone); // date is the Ngx Bootstrap selected date
specificMoment.set('hour', +time.split(':')[0]); // time is HH:mm string
specificMoment.set('minute', +time.split(':')[1]);
return specificMoment.toDate
*timeZone changes according to the user, not due to it's browser, it's an attribute of the user, so I can't set moment.tz.setDefault(...);.
What I'm facing is that .toDate is returning my current timeZone, event though it appears my different timeZone inside the moment object.
Why is it working like this and what would be a working implementation for what I need?
Ps: console.log(specificMoment.format()); returns wrong timeZone as well 2018-12-20T23:00:30-02:00.
EDIT
Turns out using const specificMoment = moment(date).tz(timeZone); and then return specificMoment.toDate() "works". It returns a Date object with 2018-12-21T05:00:00.323-0200, which is the date with specified timezone (GMT -8:00) but displayed on my current timezone (GMT -2:00).
The data is stored on my DB correctly.
Can someone explain why?
Thx.

It looks like you haven't setup moment-timezone with any data about the timezone to use.
Check out this link on Data Loading in momentjs.
I've created a JS Bin for your example that shows how to use Data Loading. Check it out here.
e.g.
moment.tz.add([
'America/Los_Angeles|PST PDT|80 70|0101|1Lzm0 1zb0 Op0',
'America/New_York|EST EDT|50 40|0101|1Lz50 1zb0 Op0'
]);

momentjs: how to get the date in a specific timezone

In a nutshell I want moment to respect server's timezone. I've set my machine's timezone to Alaska but I'm passing a Brisbane timezone string to moment. Now I need moment.toDate to return a date instance in the same timezone as the one I pass in the moment constructor; e.g.
m = moment("2016-11-20T08:00:00+10:00")
m.format() // "2016-11-20T08:00:00+10:00"
m.toDate() // Sat Nov 19 2016 13:00:00 GMT-0900 (AKST)
I want to get a Date instance from moment that's in the input timezone; e.g. somehow get toDate to return Sun Nov 20 2016 08:00:00 GMT+1000 (AEST).
FWIW I have tried the same code with and without moment.tz.setDefault and while it correctly changes the format result, toDate always uses the machine's timezone!
Update
The reason I need this behaviour is that some JavaScript libraries and controls don't understand moment and only work with Date and the time/date gets skewed when presented back by them. One example, the one I'm currently dealing with, is jQuery UI date picker control. I want the date picker to show the current date as it's on the server (or on a specific timezone).
Thanks in advance.

The Date object represents the time in UTC internally, and can only use the time zone of the machine its running on when projected.
There's absolutely no way to produce a Date object that uses an arbitrary time zone. Any examples you may come across that try to manipulate the Date object (such by adding or subtracting time zone offsets) are fundamentally flawed.
Moment itself has great time zone support, including the moment-timezone extension for working with named time zones instead of just time zone offsets. But once you go back to a Date object - you're back at the mercy of the behavior of that object.
Sorry, but there's no way to achieve what you are asking. Perhaps you could elaborate as to why you wanted to do this, and I could recommend a workaround.
Update: With regards to your update, usually there is a mechanism for getting the value from a date picker as text, rather than as a date object. With the example of the jQuery UI date picker control, the onSelect event gives it to you as text already, or you can simply call .val() instead of .datepicker('getDate') to get the text out of the field. Once you have a textual value, you can then parse it with moment however you like.
Similarly, when setting the value, you don't necessarily need a Date object. You could just set the value of the textbox as a string, or you can pass a string to the setDate function.
In most cases, you won't have to go through a Date object. But if for some reason you do, then you'll need to artificially construct one with something crazy like:
var d = new Date(m.format('YYYY/MM/DD'));
Normally, I'd be against that - but if it's just there to get the pass a value to a UI control, then it's probably ok.

This will get you a moment in the same timezone as the moment string, but toDate is always in the local timezone.
d = "2016-11-20T08:00:00+10:00"
m = moment(d).utcOffset(d)
m.format()
m.toDate()

How to send AngularStrap datepicker value without timezone?

I'm wondering if it's possible to use AngularStrap's datepicker without it keeping the user's locale's timezone information. In our application we want to handle Contract objects that have an expiration date.
When adding or editing the contract object, there is a datepicker field for selecting the date. The following thing happens:
The user selects the date (e.g. 2013-10-24)
Angular binds the javascript date object to the ng-model field
The binded date object is in the user's timezone (e.g. GMT+3)
The user submits the form
The date gets sent to the server using Angular's $http service
In step 5 the date is converted to UTC format. The selected date was GMT+3 2013-10-24 at midnight, but the UTC conversion changes the date to 2013-10-23 at 9pm.
How could we prevent the conversion, or use UTC dates during the whole process? We don't want the contract's date to change based on the user's local timezone. Instead, we want the date to be always 2013-10-24, no matter what timezone.
Our current solution was to make small changes to the AngularStrap library so that the date won't change when sent to the server.
If we could get the user's selected timezone in the server, we could make another conversion there, but the server doesn't have that information.
All ideas are appreciated!

The issue isn't AngularStrap. Its just how javascript dates work and how JSON formats them for transmission. When you turn a javascript date object into a JSON string, it formats the string as UTC.
For example, I'm in Utah and it is now 07:41 on 2013-10-24. If I create a new javascript date and print it to the console it will say:
Thu Oct 24 2013 07:41:19 GMT-0600 (MDT)
If I stringify that same date (using JSON.stringify(date), I get:
"2013-10-24T13:41:47.656Z"
which you can see is not in my current timezone, but is in UTC. So the conversion is happening just before the form gets sent to the server when it gets converted from a javascript object to a JSON string.
The easiest way to do it would be to just change the date to a string of your own choosing prior to sending the date to the server. So instead of letting JSON change the date to UTC, (assuming you don't care about the time of day) you could just do something like this:
var dateStrToSend = $scope.date.getUTCFullYear() + '-' + ($scope.date.getUTCMonth() + 1) + '-' + $scope.date.getUTCDate();
That will give you a UTC-based string that looks like '2013-10-24' and then you can send that to the server, instead of the JSON format which includes the time info. Hopefully that helps.
UPDATE: As #Matt Johnson said, there are two ways to do it. You said: How could we prevent the conversion, or use UTC dates during the whole process?. If you want to use UTC, then use my above explanation. If you want to just "prevent the conversion", you could use the following:
var dateStrToSend = $scope.date.getFullYear() + '-' + ($scope.date.getMonth() + 1) + '-' + $scope.date.getDate();

A bit late but I spent my afternoon on this and someone might find it useful.
Another way to do this declaratively is to use the dateType, dateFormat and modelDateFormat attributes. Set these in either the config or the HTML e.g
angular.module('app').config(function ($datepickerProvider) {
angular.extend($datepickerProvider.defaults, {
dateFormat: 'dd-MMMM-yyyy',
modelDateFormat: "yyyy-MM-ddTHH:mm:ss",
dateType: "string"
});
});
DateFormat is the format the date will be displayed to the user in the date picker while modelDateFormat is the format it will be converted to before being bound to your model.
I also had default values coming from the server which I needed to be bound to the datepicker on page load. I therefore had to update the format the server serialized dates in JSON to match the modelDateFormat. I am using Web API so I used the below.
var jsonSettings = Formatters.JsonFormatter.SerializerSettings;
jsonSettings.DateFormatString = "yyyy-MM-ddTHH:mm:ss";

The "Angular way" is to use the $filter service to format the date returned by the datepicker.
Example (HTML):
{{inpDate | date: 'dd-MM-yyyy'}}
Example (JS):
$scope.processDate = function(dt) {
return $filter('date')(dt, 'dd-MM-yyyy');
}
Plunker here

How to change the date format in JavaScript?

I am using one jquery date picker,
with using picker i am getting date in like this format
Friday, May 21, 2010
Now i want to add one day in this date so i think, i can only do if i change the date in exact format like
21/5/2010
I want to only convert that bcz i want to add one day to the particular date.
So what do u suggest me? How can I do that?
Can i do without converting it ?
thanks in advance....

Take a look at http://docs.jquery.com/UI/Datepicker#option-dateFormat

datejs may be useful to you.

In addition to the formatting options given by others, you should add using date objects rather than to the string representation of the date object.
I.E.
// add 5 days to today
var myDate=new Date();
myDate.setDate(myDate.getDate()+5);

I think you need to detail what jQuery plugin do you use.
Is it this one? http://jqueryui.com/demos/datepicker/
If so, then when you cann getDate method, you'll get Date object representing a date. You can easily manipulate it.

The date format has nothing to do with how dates are stored; it only affects the way dates are displayed. JavaScript has a native Date object and jQuery UI's Datepicker allows to access such object:
http://jqueryui.com/demos/datepicker/#method-getDate
Once you have a Date object, you can alter it to suit your needs:
https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Date
Finally, you can feed it back into Datepicker:
http://jqueryui.com/demos/datepicker/#method-setDate