JavaScript Date Format

originaly created by Steven Levithan

note from lflfm: I created this repository since there is no official one and I wanted it to be multi-language out of the box (I have a need to show more than one language at a time). So my only change is making the strings multi-language (which you can see on the commit history, as I first posted the exact, original code)

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(directly from the original post) Here are some examples of how this script can be used:

var now = new Date();

now.format("m/dd/yy");
// Returns, e.g., 6/09/07

// Can also be used as a standalone function
dateFormat(now, "dddd, mmmm dS, yyyy, h:MM:ss TT");
// Saturday, June 9th, 2007, 5:46:21 PM

// You can use one of several named masks
now.format("isoDateTime");
// 2007-06-09T17:46:21

// ...Or add your own
dateFormat.masks.hammerTime = 'HH:MM! "Can\'t touch this!"';
now.format("hammerTime");
// 17:46! Can't touch this!

// When using the standalone dateFormat function,
// you can also provide the date as a string
dateFormat("Jun 9 2007", "fullDate");
// Saturday, June 9, 2007

// Note that if you don't include the mask argument,
// dateFormat.masks.default is used
now.format();
// Sat Jun 09 2007 17:46:21

// And if you don't include the date argument,
// the current date and time is used
dateFormat();
// Sat Jun 09 2007 17:46:22

// You can also skip the date argument (as long as your mask doesn't
// contain any numbers), in which case the current date/time is used
dateFormat("longTime");
// 5:46:22 PM EST

// And finally, you can convert local time to UTC time. Either pass in
// true as an additional argument (no argument skipping allowed in this case):
dateFormat(now, "longTime", true);
now.format("longTime", true);
// Both lines return, e.g., 10:46:21 PM UTC

// ...Or add the prefix "UTC:" to your mask.
now.format("UTC:h:MM:ss TT Z");
// 10:46:21 PM UTC

//------------------------------------------------------------------------------
//addition by lflfm:
// language code can be passed as 3rd parameter to date prototype
now.format(undefined,undefined,'de');
// 'Die Feb 19 2019 23:42:50'
now.format('dddd, dd mmmm (mmm) yyyy',undefined,'de');
// 'Dienstag, 19 Februar (Feb) 2019'

// or we can set it on the dateFormat object (which is now exported for node.js usage)
const {dateFormat} = require('sl_dateFormat');

dateFormat(new Date);
//'Tue Feb 19 2019 23:45:33'
dateFormat(new Date,undefined,undefined,'pt');
//'Ter Fev 19 2019 23:45:53'

dateFormat.setLang('de');
dateFormat(new Date);
//'Die Feb 19 2019 23:46:58'

Masks:

Mask	Description
d	Day of the month as digits; no leading zero for single-digit days.
dd	Day of the month as digits; leading zero for single-digit days.
ddd	Day of the week as a three-letter abbreviation.
dddd	Day of the week as its full name.
m	Month as digits; no leading zero for single-digit months.
mm	Month as digits; leading zero for single-digit months.
mmm	Month as a three-letter abbreviation.
mmmm	Month as its full name.
yy	Year as last two digits; leading zero for years less than 10.
yyyy	Year represented by four digits.
h	Hours; no leading zero for single-digit hours (12-hour clock).
hh	Hours; leading zero for single-digit hours (12-hour clock).
H	Hours; no leading zero for single-digit hours (24-hour clock).
HH	Hours; leading zero for single-digit hours (24-hour clock).
M	Minutes; no leading zero for single-digit minutes.
MM	Minutes; leading zero for single-digit minutes.
s	Seconds; no leading zero for single-digit seconds.
ss	Seconds; leading zero for single-digit seconds.
l orL	Milliseconds. l gives 3 digits. L gives 2 digits.
t	Lowercase, single-character time marker string: a or p.
tt	Lowercase, two-character time marker string: am or pm.
T	Uppercase, single-character time marker string: A or P.
TT	Uppercase, two-character time marker string: AM or PM.
Z	US timezone abbreviation, e.g. EST or MDT. With non-US timezones or in the Opera browser, the GMT/UTC offset is returned, e.g. GMT-0500 GMT/UTC timezone offset, e.g. -0500 or +0230.
S	The date's ordinal suffix (st, nd, rd, or th). Works well with d.
'…' or "…"	Literal character sequence. Surrounding quotes are removed.
UTC:	Must be the first four characters of the mask. Converts the date from local time to UTC/GMT/Zulu time before applying the mask. The "UTC:" prefix is removed.

And here are the named masks provided by default (you can easily change these or add your own):

Name	Mask	Example
default	ddd mmm dd yyyy HH:MM:ss	Sat Jun 09 2007 17:46:21
shortDate	m/d/yy	6/9/07
mediumDate	mmm d, yyyy	Jun 9, 2007
longDate	mmmm d, yyyy	June 9, 2007
fullDate	dddd, mmmm d, yyyy	Saturday, June 9, 2007
shortTime	h:MM TT	5:46 PM
mediumTime	h:MM:ss TT	5:46:21 PM
longTime	h:MM:ss TT Z	5:46:21 PM EST
isoDate	yyyy-mm-dd	2007-06-09
isoTime	HH:MM:ss	17:46:21
isoDateTime	yyyy-mm-dd'T'HH:MM:ss	2007-06-09T17:46:21
isoUtcDateTime	UTC:yyyy-mm-dd'T'HH:MM:ss'Z'	2007-06-09T22:46:21Z

A couple issues:

• In the unlikely event that there is ambiguity in the meaning of your mask (e.g., m followed by mm, with no separating characters), put a pair of empty quotes between your metasequences. The quotes will be removed automatically.
• If you need to include literal quotes in your mask, the following rules apply:
  • Unpaired quotes do not need special handling.
  • To include literal quotes inside masks which contain any other quote marks of the same type, you need to enclose them with the alternative quote type (i.e., double quotes for single quotes, and vice versa). E.g., date.format('h "o\'clock, y\'all!"') returns 6 o'clock, y'all. This can get a little hairy, perhaps, but I doubt people will really run into it that often. The previous example can also be written as date.format("h") + "o'clock, y'all!".

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