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.

When converting date, I get previous day

I want to convert a string into a date "as it is".
const date = "8/16/2019"
console.log(new Date(date))
However, I get:
As you can see I get the prevous day. I was thinking that it might be a timezone issue, even though there is no timezone that I am converting it from.
Any suggestions how to convert is as it is?
I appreciate you replies!

If your format is consistent, you could split on / and use Date.UTC. Creating your new Date from that would ensure it's UTC.
const date = "8/16/2019"
const [month,day,year] = date.split("/");
const utcDate = Date.UTC(year,month-1,day);
console.log(new Date(utcDate));

const date = "8/16/2019"
console.log(new Date(date).toLocaleString("en-US", {timeZone: "Asia/kolkata"}))
Note:- You need to add timezone

You can use toLocaleDateString
console.log(new Date("8/16/2019").toLocaleDateString('en-us', {timeZone: "Asia/Kolkata"}))

new Date("8/16/2019") will create a date object using your current timezone. Add a "Z" at the end if you want your date to be in UTC.
console.log(new Date("8/16/2019Z"))
EDIT
It appears that Firefox is not implementing the parsing of standard date format. Unfortunately until recently how exactly was a date parsed was completeley based on heuristics and intrinsically non portable.
Looking at Firefox bug tracker seems the issue has been discussed but the problem is still present (some toolkit just works around by replacing "Z" with "+00:00" before calling the parser).
The only way to be sure on every browser is to parse the string yourself and build the date from the fields. I didn't notice because I'm using chrome instead (in both chrome and Node works as expected).
EDIT 2
After more investigation seems the standard requires that:
If you use yyyy-mm-ddThh:mm:ssz then you get what ISO format for datetime defines it to be. Also the syntax described in the standard is not very precise and for example is not clear to me if the time zone can be present when no time is present (Chrome says yes, Firefox says no).
If you use another format then anything goes (so for example there is no string that is guaranteed to issue an invalid date response).
In other words new Date("8/16/2019") is not portable Javascript (with the meaning that you don't know what date / time / timezone you will get, if any). Either you parse yourself the date or you just live with what that version of that Javascript engine in that moment decides to give you.

Get current timestamp in NodeJS in DD-MM-YY-23:59:42 format

I am running NodeJS 8 in AWS Lambda and want to timestamp and attach to an S3 the current day, month, year and current time when the function runs.
So if my function was running now, it would output 220619-183923 (Todays date and 6.39pm and 23 seconds in the evening.)
For something a little complex like this do I need something like MomentJS or can this be done in pure Javascript?
Eventually this will make up a S3 URL such as
https://s3.eu-west-2.amazonaws.com/mybucket.co.uk/BN-220619-183923.pdf
UPDATE
The webhook appears to have some date/time data albeit in slightly different formats that weren't outputted in the Lambda function, so these could prove useful here. Can ':' be used in a URL and could the UTC which I assume is in milliseconds be converted into my desired format?
createdDatetime=2019-06-22T18%3A20%3A42%2B00%3A00&
date=1561231242&
date_utc=1561227642&
Strangely, the date_utc value which is actually live real data. Seems to come out as 1970 here?! https://currentmillis.com/

You don't need moment. I have included a solution that is quite verbose, but is understandable. This could be shorted if needed.
Since you are using S3, you might also consider using the UTC versions of each date function (ie. .getMonth() becomes .getUTCMonth())
Adjust as needed:
createdDatetime= new Date(decodeURIComponent('2019-06-22T18%3A20%3A42%2B00%3A00'))
date=new Date(1561231242 * 1000);
date_utc=new Date(1561227642 * 1000);
console.log(createdDatetime, date, date_utc)
const theDate = createdDatetime;
const day = theDate.getUTCDate();
const month = theDate.getUTCMonth()+1;
const twoDigitMonth = month<10? "0" + month: month;
const twoDigitYear = theDate.getUTCFullYear().toString().substr(2)
const hours = theDate.getUTCHours();
const mins = theDate.getUTCMinutes();
const seconds = theDate.getUTCSeconds();
const formattedDate = `${day}${twoDigitMonth}${twoDigitYear}-${hours}${mins}${seconds}`;
console.log(formattedDate);
UPDATE based upon your update: The code here works as long as the input is a JavaScript Date object. The query parameters you provided can all be used to create the Date object.

You can definitely use MomentJS to achieve this. If you want to avoid using a large package, I use this utility function to get a readable format, see if it helps
https://gist.github.com/tstreamDOTh/b8b741853cc549f83e72572886f84479

What is the goal of creating this date string? If you just need it as a human-readable timestamp, running this would be enough:
new Date().toISOString()
That gives you the UTC time on the server. If you need the time to always be in a particular time zone, you can use moment.

Moment time difference won't use moment timezone but users computer time

I'm attempting to display a duration ticker for something. The start time is always in London time. It works perfectly for people in England/the same timezone, however when people in other time zones look at the duration it displays the wrong value (If you're in a timezone behind England => negative values/too small values, timezone ahead => value too large).
My solution to this was to use moment-timezone. I added the moment timezone data correctly I've attempted to use this timezone data (code simplified and separated into individual lines for easier readability):
let londonTimeNow = moment().tz('Europe/London'),
jobStartTime = moment(job.start, 'DD/MM/YYYY HH:mm:ss'),
diff = londonTimeNow.diff(jobStartTime);
duration = moment.duration(diff).format('HH:mm:ss', {trim: false});
I was hoping this would then get the current time in London and compare to the start time no matter where you are in the world. However, it seems the diff function converts the time to the user's computer time. I tried formatting the londonTimeNow to be a string, but then the diff function doesn't work.
Note, I've debugged and moment().tz() is working correctly, I've tried with other time zones and it gets the correct time in the zone specified.
Any ideas?
EDIT:
It seems I can get it working by manually setting the offset property of 'londonTimeNow' to 0. However this doesn't feel quite right to me. I'd prefer a solution that seems less like a hack.

You should specify the jobstart time in the same way you declare london time using the same timezone:
jobStartTime = moment.tz(jobStart, 'DD/MM/YYYY HH:mm:ss','Europe/London'),
This will set the job start time using the same timezone.

Could you add expected output or specify what you mean by 'diff converts the time'?
The result of diff is a duration and is not in any timezone.
Other than that, the problem seems to be in not using timezone for task start.
Try this:
let londonTimeNow = moment().tz('Europe/London'),
jobStartTime = moment(job.start, 'DD/MM/YYYY HH:mm:ss').tz('Europe/London'),
diff = londonTimeNow.diff(jobStartTime);
duration = moment.duration(diff).format('HH:mm:ss', {trim: false});

Using timezones with moment.js fromNow() or from()

I want to show users how long has been elapsed since they performed an action.
The date+time of the action happening is stored on the server, in the server's timezone. That's what's causing the trouble, since if the user's computer's timezone is 12 hours ahead of the server's timezone, then if the user adds something right now, moment.js will show '12 hours ago' as the output of fromNow() rather than just now.
To try to solve this, I'm trying the following method:
var actionTime = moment( action.timeStamp);//time of when user performed action
var serverTime = moment().zone('-07:00'); //current server time
console.debug( serverTime);//outputs Wed Sep 11 2013 15:19:51 GMT-0700
var timeAgo = serverTime.from( actionTime);
But despite of all this, timeAgo still shows the difference between the client's timezone and the server's timezone (i.e showing '12 hours ago' instead of 'now');
Anyone know how to fix this or what I'm doing wrong?

Ideally, you would want to pass a UTC timestamp from your server to the client. That doesn't mean you have to switch your whole server over to UTC, it just means that you would convert from the time in your database to UTC on the server before sending it over the web. Sure, it would be even better if you actually stored times in UTC, but you said you aren't in a position to make that sort of change right now. But let's just work off the assumption that you can't change anything at all on the server.
We'll also assume that your server is fixed to the UTC-07:00 offset. In real life, this would only be true for places like Arizona that don't follow daylight saving time. So if you are in Los Angeles and are in Pacific Time, then some of your data is based on UTC-07:00, but some of it is based on UTC-08:00. That requires a lot more work if you want to do it in JavaScript.
Let's also assume that the input is already a string in ISO8601 format. (If it's not, then let me know and I will adjust this code.)
var s = "2013-09-11 18:00:00"; // from action.timeStamp
var actionTime = moment(s + "-07:00", "YYYY-MM-DD HH:mm:ssZ");
var timeAgo = actionTime.fromNow();
The reason your other code didn't work is because in the first line, you are affected by the time zone of the browser. The zone setter in the second line just changes the zone for formatting, not changing the actual moment in time.
Also, when you dump a moment to the console for debugging, make sure you format it for output. Otherwise you are just looking at its internal property values, which may or may not make sense directly.

I have solved it in a different way, maybe this option was not possible back when the question was asked, but might be easier now.
I used moment-timezone.js (which requires moment.js 2.6.0+).
I set the default timezone to my server's timezone like this:
moment.tz.setDefault("America/New_York"); // "America/New_York" in my case
and then just use it normally. fromNow() will use the timezone in the client to calculate the time that has passed since that moment.
moment(myDatetime).fromNow();

i had the same issue and used the above comments to modify my code. I did the following to get it resolved:
transform(value: string) {
var time = moment(value).utc();
return moment(time, "YYYYMMDD").fromNow();
}
I was missing the .utc() to convert it before I applied the .fromNow()
Things to note this is being used within a Pipe for Ionic 3 and the above code is from the pipe logic.