Get millis when using new Date().toLocaleTimeString()

Question

I have this code:

v.d = new Date().toLocaleTimeString();

it yields something like this:

20:11:40

So this is the time of day to the second, without milliseconds. My question is: is there a built in call that can show just the time with milliseconds?

I am looking for something like this (to the millisecond):

20:11:40.124

*toLocaleTimeString* is implementation dependent, you can't rely on getting any particular format. You might get "8:11:40 pm", or lots of other values. — RobG, May 01 '18 at 22:25
@RobG I think you should have not marked this question as a duplicate; this question here is very specific about `toLocaleTimeString` which the other Q/A has really nothing related except that both are about JS datetimes. Actually there is a living standard way to get the milliseconds formated using `(new Date).toLocaleTimeString([], { hour12: false, hour: '2-digit', minute: '2-digit', fractionalSecondDigits: 3 })` will return something like `03:40:59.077`. Too pity I can't submit an answer! — Christos Lytras, Apr 12 '22 at 00:46
@ChristosLytras—there are already 32 answers at the duplicate for formatting time, which is what the OP wants. If you have another answer, post it there. Not specifying a language for *toLocale\** methods means the returned timestamp will be based on the host's language and may not be what you expect. — RobG, Apr 12 '22 at 03:56
@RobG IMO javascript datetime formating must not be limited to one question and many answers; there are many APIs and libraries to do that and we should not generalize every question about datetime formating. This one here is a very specific question about how to add milliseconds using **built in** method/ways with `toLocaleTimeString` that the other Q/A does not ask, but rather focuses on general datetime formating. IMO, we should not sumup every formating related question to one question and many answers. — Christos Lytras, Apr 12 '22 at 13:31

Alexander Mills · Accepted Answer · 2018-05-01T03:43:42.210

5

This works, but I am looking for something more compact if possible:

 const d = new Date();
 v.d = d.toLocaleTimeString() + `.${d.getMilliseconds()}`;

this yields:

20:17:30.744

note that to make this work well, you need to add this part: Formatting milliseconds to always 3 digits for d.getMilliseconds() call

edited May 01 '18 at 03:43

answered May 01 '18 at 03:18

Alexander Mills

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I think this is going to be the easiest way. Just turn put it in a function and pass the date in for convenience. – Cory Kleiser May 01 '18 at 03:32
Yeah looking for something as performant as possible, but I guess this will have to do for now – Alexander Mills May 01 '18 at 03:42
2

You can't rely on *d.toLocaleTimeString* returning a particular format. Much better to manually format the string. – RobG May 01 '18 at 22:27

score 2 · Answer 2 · answered May 01 '18 at 03:24

2

There’s to ISOString(). But stepping back a level, with that exception there’s no standard for formatting dates in js. So you can use toISOString or build up your own string with individual date functions.

answered May 01 '18 at 03:24

Geuis

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you mean `Date.prototype.toISOString()` right? – Alexander Mills May 01 '18 at 03:26
1

Yah. Typed from my phone. – Geuis May 01 '18 at 05:15

Cory Kleiser · Answer 3 · 2018-05-01T04:34:17.683

I did find one issue with your original solution. When I perform it it yields hh:mm:ss PM.mil. I assume you want hh:mm:ss.mil Here is that solution written as a function so you can pass the date object in and get the proper format:

const d = new Date()

const getTimeWithMilliseconds = date => {
  const t = d.toLocaleTimeString();
  return `${t.substring(0,8)}.${date.getMilliseconds() + t.substring(8,11)}`;
}

console.log(getTimeWithMilliseconds(d));

Or if you want it in 24 hour format:

const d = new Date()

const getTimeWithMilliseconds = date => {
  return `${date.toLocaleTimeString('it-US')}.${date.getMilliseconds()}`;
}

console.log(getTimeWithMilliseconds(d));

score 1 · Answer 4 · answered May 01 '18 at 22:38

You can't depend on toLocaleTimeString returning a specific format as it's implementation dependent. It's much more reliable to build the format yourself, e.g.:

function getFormattedTime(date) {
  var d = date || new Date();
  var z = n => ('0'+n).slice(-2);
  var zz = n => ('00'+n).slice(-3);
  return `${z(d.getHours())}:${z(d.getMinutes())}:${z(d.getSeconds())}.${zz(d.getMilliseconds())}`;
}

console.log(getFormattedTime());
console.log(getFormattedTime(new Date(2018,1,1)));
console.log(getFormattedTime(new Date(2018,4,30,23,51,12,89)));

Also see Where can I find documentation on formatting a date in JavaScript?

Get millis when using new Date().toLocaleTimeString()

4 Answers4