We Keep Coding

Javascript Date comparison coming from server and new Date()

I have a date coming from database which is 2022-10-31 11:33:07.861Z, and in my js file I have this date is saved in a variable :
function test() {
let now = new Date().toLocaleString('en-GB', { timeZone: 'Europe/London'}); // I need now to be Europe/london time
let dateFromDb = db_date; // 2022-10-31 11:33:07.861Z
// I have a function which takes ^ above date and returns this : Mon Oct 31 2022 11:33:07 GMT+0000 (Greenwich Mean Time)
let formatedDate= this.toDate(dateFomDb); // returns : Mon Oct 31 2022 11:33:07 GMT+0000 (Greenwich Mean Time)
}
When I console.log(now, typeOf now) I get this: 02/11/2022, 23:24:52 string
and console for formatedDate returns this : Mon Oct 31 2022 11:33:07 GMT+0000 Object
I need to compare both dates :
return newDate <= now; // expect it to true or false;
Can anyone please suggest me how can I do this ?
I tried to cast both dates toLocalString but its string from I need object.

JS setHours on date is not working correctly

I have the following code to increment the hours in a date:
let timerExpireDate = new Date(countdownStartDate);
console.log(`original date is ${timerExpireDate}`);
console.log(`add on ${countdownHours} hours`);
timerExpireDate.setHours(timerExpireDate.getHours() + countdownHours);
console.log(`New date is ${timerExpireDate}`);
However it also seems to be incrementing the days by 6, here is the console log:
original date is Sun Jul 19 2020 16:36:39 GMT+0800 (Taipei Standard Time)
add on 2 hours
New date is Sat Jul 25 2020 18:36:39 GMT+0800 (Taipei Standard Time)
What am I doing wrong here?

It is likely that countdownHours is of type string instead of number, so timerExpireDate.getHours() + countdownHours is '162' (6 days later) instead of 18.
The fix is to cast countdownHours to number first, like countdownHours = +countdownHours.

Converting timezones in javascript resulted in very strange results, am I doing something wrong or is it a bug?

After isolating the problem in my current project .... I think something is not working currently with the Date object in javascript.
But I don't want to be arrogant because maybe I am doing something wrong, is it a bug? or am I doning something wrong?
I want to convert a date to diffrent time zone in javascript, I made this function:
function ConvertToTimeZone(date, timezone) {
let convertedTimeString = date.toLocaleString("en-US", {hour12: false, timeZone: timezone})
return new Date(convertedTimeString)
}
Then I am using it like this:
let testDate = new Date("Thu May 21 2020 17:04:05 GMT-0700 (Pacific Daylight Time)");
let convertedDate = ConvertToTimeZone(testDate, "Europe/London");
Or like this:
let testDate = new Date("Thu May 21 2020 18:04:05 GMT-0700 (Pacific Daylight Time)");
let convertedDate = ConvertToTimeZone(testDate, "UTC");
But something wrong is happening when I use this date:
let testDate = new Date("Thu May 21 2020 17:04:05 GMT-0700 (Pacific Daylight Time)");
let convertedDate = ConvertToTimeZone(testDate, "UTC");
with that last exmaple convertedDate end up with Invalid Date {}
And when I look closely in my ConvertToTimeZone the result of date.toLocaleString(...) is 5/22/2020, 24:04:05 which looks strange because the hours of that time cannot be 24 (it should be 0)

Include millisecond data in JavaScript Date

I have a requirement to send the current system date to microservices on search. The time should include milliseconds information as well. For now I was sending new Date() for the same and it looked like:
Thu Aug 31 2017 15:06:37 GMT+0530 (India Standard Time)
However I need the milliseconds information as well so the time should look like:
Thu Aug 31 2017 15:06:37.228 GMT+0530 (India Standard Time)
Here 228 is the millisecond at that moment that I can extract using getMilliseconds() method of date. The question is how can I add this in the date so that it works for all locations wherever the application is accessed?

If you don't mind having the result as a string, this will show the output you are looking for:
// ES5
var fmtDateMsES5 = function(date) {
var splitDate = date.toString().split(' ');
splitDate[4] = splitDate[4] + '.' + date.getMilliseconds();
return splitDate.join(' ');
}
// log output (ES5)
console.log('ES5 output\n', fmtDateMsES5(new Date()));
// ES6
const fmtDateMsES6 = date => {
const splitDate = date.toString().split(' ');
splitDate[4] = `${splitDate[4]}.${date.getMilliseconds()}`;
return splitDate.join(' ');
};
// log output (ES6)
console.log('ES6 output\n', fmtDateMsES6(new Date()));
// ES5 and ES6 functions logged simultaneously
console.log(
`\nES5 and ES6 functions logged simultaneously`,
`\n${'-'.repeat(55)}`,
`\nES5 output ${fmtDateMsES5(new Date())}`,
`\nES6 output ${fmtDateMsES6(new Date())}`
);

Initially I saw the format method on the Date object but this is not built-in and requires a library.
If you must use a time library I would recommend the excellent moment.js and use the "SSS" syntax to get the milliseconds, for example:
var now = moment().format('MMM DD h:mm.SSS A');
//Sep 12 8:21.167 AM
http://jsfiddle.net/kLL2eobh/

Easy way to convert a timestamp to a human readable date

I have the following timestamp: 2016-03-29T14:14:43.000Z. Is there any easy way to use JavaScript to make it look something like the following: Mar 29, 2016 2:14p? I tried using Date.parse() but it didn't seem to do anything.

{{yourValue| date:"MMM d, yyyy h:ma"}}

var ts = "2016-03-29T14:14:43.000Z";
var date = new Date(ts);
console.log(date); // Displays Tue Mar 29 2016 16:14:43 GMT+0200 (Romance Summer Time)
Is that what you need ?
var ds = date.toUTCString();
console.log(ds.substr(0,24)); // Displays Tue Mar 29 2016 16:14:43