Adding +GMT in Javascript - javascript

Good day, I would like to ask how can I add any timezone in my date object?
My scenario is I have created a date picker and time picker and they will generate a DateTime Object looking like "01/02/2003 4:56 PM" I just need to add the GMT +/- (Timezone) in the date time object so it can look like "01/02/2003 4:56 PM GMT + 0700" and my backend will process the conversion to utc.
Is it possible? Thank you and good day.

You can use new Date("01/02/2003 4:56 PM") which will return time zone information.

Related

Why does ISO date in Mongodb display one day earlier?

The stored date looks like this:
...
"date_of_birth" : ISODate("1920-01-02T00:00:00Z"),
...
Using moment, it is formatted in the model (in order to populate the input for updating the document) like this:
AuthorSchema
.virtual('date_of_birth_update_format')
.get(function(){
// format in JavaScript date format (YYYY-MM-DD) to display in input type="date"
return this.date_of_birth ? moment(this.date_of_birth).format('YYYY-MM-DD') : '';
});
Retrieved from the collection and displayed, it displays as one day earlier like this:
01/01/1920
I would appreciate any help to resolve this.
The date from mongo is always in GMT, and your server might be in other timezone. You need to convert date to GMT before formatting.
var moment = require("moment-timezone")
AuthorSchema.virtual('date_of_birth_update_format').get(function(){
return this.date_of_birth ? moment(this.date_of_birth).tz('GMT').format('YYYY-MM-DD') : '';
});
The Z in the ISO 8601 format implies 'GMT' i.e. 1920-01-02T00:00:00+0000. Moment will take your timezone into consideration. If you are in the continental US, your time zone offset is -0400—-0800.
1920-01-02T00:00:00Z = 1920-01-01T6:00:00-0600 In Pacific Standard Time for example.
It depends on the time zone which you are in for example am in India so GMT for me is +5:30 so whenever I retrieve from db I would add up 5:30 to time so that it matches the date and to answer why it storing it a day before because it stores date in ISO format that's why
Same problem here. I was using EJS to show the date retrieved from the MongoDB database. I'm not sure if the problem is with EJS, but I solved it like this:
All I had to do was to set the timeZone to GMT in the front-end:
date.toLocaleString("pt-BR", {timeZone:"GMT", day: "numeric", month: "numeric", year:"numeric"});

moment-timezones.js, how to convert date in spesific timezone to utc, disregarding my local timezone?

my system uses timezone UTC+03:00 ,
im trying to get a date in string format, represented by NY timezone,
and convert it to a Date object in utc
const dateInNY = moment.tz(xlsxDate, "M/D/YYYY h:mm a", "America/New_York")
.tz("Z").toDate();
doesnt work correctly
how am i even suppose to convert to utc time?
-----------edit---------------
i got it to work, using the timezone "Africa/Accra" , where UTC offset is 0, and ther is no daylight savings time:
moment.tz(xlsxDate, "M/D/YYYY h:mm a", "America/New_York").tz("Africa/Accra")
but this solution is a bad workaround, and if the government of Accra decide to change the time laws, will stop working!
is there a way to set the utc offset to 0 in momentjs-timezones?
As Álvaro González mentioned, that Date object does not contain Time zone information.
I do the following:
new Date(moment.tz(date, currentTimezone).tz(newTimezone).format('YYYY/MM/DD HH:mm:ss'))
where date is a date object or a string (e.g. '2017-10-30 16:30:00.0000')
so, I change date from currentTimezone to newTimezone and after that new Date object will be returned
Let's change '2017-10-30 16:30:00.0000' from UTC to America/Toronto (UTC-4)
new Date(moment.tz(date, 'UTC').tz('America/Toronto').format('YYYY/MM/DD HH:mm:ss'))
And I got
Mon Oct 30 2017 12:30:00 GMT+0400
GMT+0400 is my timezone and console.log() just shows it with any
date object and it can mislead you. Please, don't look at the this
timezone.
Let's change '2017-10-30 16:30:00.0000' from Europe/Samara (UTC+4) to America/Toronto (UTC-4)
new Date(moment.tz('2017-10-30 16:30:00.0000', 'Europe/Samara').tz('America/Toronto').format('YYYY/MM/DD HH:mm:ss'))
Firstly, moment.tz undertands that date has no timezone information and associate with Europe/Samara (UTC+4)
timezone. After that computes difference between new and old
timezone (it's -8 hours in this case)
And returns result
Mon Oct 30 2017 08:30:00 GMT+0400
And answer on your question
If xsltDate is a date object or string which do not contain timezone information
dateUTC = new Date(moment.tz(xlsxDate, "America/New_York").tz("UTC").format('YYYY/MM/DD HH:mm:ss'));
If xsltDate contain timezone information (e.g.'2013-06-01T00:00:00-04:00'), then no need to tell moment.tz which timezone xlsxDate has, just mention a new timezone
dateUTC = new Date(moment.tz(xlsxDate, "UTC").format('YYYY/MM/DD HH:mm:ss'));
Short answer is that you cannot.
The .toDate() method of the Moment library returns a native Date object. Such objects do not keep memory of any specific time zone (that's one of the reasons to use Moment in the first place), they just keep track of the exact time moment represented and merely pick a time zone when formatting to string, which is either UTC or the browser's time zone (not an arbitrary one).
The long answer is that you're probably getting correct results but are printing them with a method that uses the browser's time zone.
i found a function that does what i was trying to do, it belongs to the momentjs library itself: utcOffset(n) sets the offset to n.
(i also had to explicitly write the date string format correctly, thanks VincenzoC)
this is the code i was trying to write:
const dateInNY = moment.tz(xlsxDate, "M/D/YYYY h:mm a", "America/New_York");
const dateUTC = dateInNY.utcOffset(0).toDate();
however, the toDate function changes the timezone to my local timezone anyway, so .utcOffset(0) is redundat, and i can just use moment this way:
const dateInNY = moment.tz(xlsxDate, "M/D/YYYY h:mm a", "America/New_York");
const dateUTC = dateInNY.toDate();
and change the Date objects date to utc time later (in my case, the JSON.stringify stuff i use later does that for me)

How to convert all dates from UTC to Local time using angularJS?

I have very complex structure that I receive from server-side code.
This structure has many Date properties (of type Date).
These Date properties contain dates in UTC.
I need to convert all of them to Local.
Is there any way to do this in angularJS?
Instead of doing this one-by-one?
Maybe some global setting or options that will instruct angular to convert dates into Local automatically?
Thanks.
append " UTC" to the backend time and run that through new Date(). It'll give you the local time offset.
var backEndDate = "2016-10-20 10:00 AM" + " UTC";
console.log(new Date(backEndDate));
The first approach is change your web service to return the utc date using ISO 8601 format.
For example: "2016-10-07T22:01:00Z"
If the web service return's the date using this ISO is easy to represents the date in local time of user because the browser instances the date based on your current time zone.
For example: if i open my browser console and run this javascript code:
new Date("2016-10-07T22:01:00Z")
I will receive the date based on my time zone, that is GMT-0300.
Fri Oct 07 2016 19:01:00 GMT-0300 (SA Eastern Standard Time)
So, for angularjs code you just need write::
{{"2016-10-07T22:01:00Z" | date}}
i will receive this result:
Oct 7, 2016
Check the filter for date here
For use the filter correctly. For example:
{{"2016-10-07T22:01:00Z" | date: 'MM/dd/yyyy HH:mm'}}
The result is:10/07/2016 19:01
The second approach is convert the date from your web service for the ISO 8601 format.
Actually i had the same problem and the client web service sends me the date just like this: "2016-10-07 22:01:00"
So, i wrote a simple code to convert this date format to ISO 8601.

Convert ISO Date string to date in JavaScript

Need help to convert exactly from ISO Date string to Date:
I have an ISO string date: "2016-01-23T22:23:32.927".
But when I use new Date(dateString) to convert Date, the result is wrong:
var date = new Date("2016-01-23T22:23:32.927");
The result is: Sun Jan 24 2016 05:23:32 GMT+0700. It's not true. I want the date is 23 not 24.
Please help me. Thanks a lot!
You need to supply a timezone offset with your iso date. Since there isn't one, it assumes the date to be in GMT and when you log it out, it prints it in the timezone of your browser. I think that if you pass "2016-01-23T22:23:32.927+07:00" to new Date() you would get the value you are expecting.
JavaScript environments (browser, node,...) use a single timezone for formatting dates as strings. Usually this is your system's timezone. Based on the output you get, yours is GMT+0700.
So what happened:
The string you passed as ISO format to the Date constructor doesn't specify a timezone. In this case it is treated as UTC.
When you then output the date (I'll assume with console.log), it is converted to the timezone of your environment. In this case 7 hours where added.
If that doesn't suit you, you can change the way you output the date. This depends on what output you want, e.g.:
If you just want the UTC timezone again, you can use date.toISOString().
If you want to output it in another timezone, you can call date.getTimezoneOffset() and figure out the difference between both timezones. You'd then probably need to get the individual date parts and add/subtract the timezone difference accordingly. At this point you could consider using an existing library, taking into account their possible disadvantages.
If you're willing and able to add a dependency, I recommend using moment.js for this. It makes date handling in Javascript much more straightforward and a lot safer, and fixes your specific problem right out of the box.
To do this, 1st load it from a CDN, e.g. Moment.JS 2.14.1 minified. Then use it as follows:
var date = moment("2016-01-23T22:23:32.927");
console.log(date);
// output: Sat Jan 23 2016 22:23:32 GMT-0500
...i.e. your desired result :)
Here's a jsfiddle demonstrating this.
Use date.toUTCString()
it'll give you 23 instead of 24 as it Convert a date object to a string, according to universal time

JS get date in UTC time

I've created a date in JS like so:
var myDate = new Date('2013-01-01 00:00:00');
I assume JS reads this in as UTC time. But when I do something like myDate.getTime() the timestamp returned was something like 4AM GMT time.
Why is this? And how do I get the date as midnight in UTC time?
At least in Chrome, this works:
var myDate = new Date('2013-01-01 00:00:00 UTC');
It also works if you put GMT instead of UTC. But I don't know if this is cross-browser enough.
I live in India. Hence my timezone is the Indian Standard Time (IST) which is listed in the tz database as Asia/Kolkata. India is 5 hours 30 minutes ahead of GMT. Hence when I execute new Date("2013-01-01 00:00:00") the actual time at GMT is "2012-12-31 18:30:00".
I believe you live in America because you're in the EST timezone (GMT-04:00)? Am I right?
If you want to parse the time at GMT instead of your local timezone then do this:
new Date("2013-01-01T00:00:00+00:00");
Notice the capital T between the date and the time, and the +00:00 at the end. This is the format used to parse a given time in a specific timezone.
Given the date string "2013-01-01 00:00:00" you can convert it to the required format using the following function:
function formatDateString(string, timezone) {
return string.replace(" ", "T") + timezone;
}
Then you can create the date as follows:
new Date(formatDateString("2013-01-01 00:00:00", "+00:00"));
Another way to convert local time to GMT is as follows:
var timezone = new Date("1970-01-01 00:00:00"); // this is the start of unix time
Now that you have your own local timezone as a date object you can do:
new Date(new Date("2013-01-01 00:00:00") - timezone);
All the above methods produce the same date at GMT.
JS reads this with time zone that your computer uses.
You can try use myDate.toUTCString() for get date in UTC time.
If you want get timestamp use myDate.getTime()
Mine works simply by doing this
var datetime= new Date()
However the month is 1 low so you have to add one

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