dateformat

What is dateformat?

The dateformat npm package is a utility for formatting dates. It allows users to format dates using mask tokens, which can be either predefined or custom. It can also convert dates to strings with specified formats, and handle different locales.

What are dateformat's main functionalities?

Basic date formatting

This feature allows you to format a JavaScript date object into a string with a specified format. The code sample shows how to format the current date and time into a more readable string.

const dateFormat = require('dateformat');
const now = new Date();
dateFormat(now, 'dddd, mmmm dS, yyyy, h:MM:ss TT');

Using predefined masks

Predefined masks are built-in formats that can be used to quickly format dates. The code sample demonstrates using the 'longDate' mask to format the current date.

const dateFormat = require('dateformat');
const now = new Date();
dateFormat(now, 'longDate');

UTC date formatting

This feature allows for formatting dates in UTC. The code sample uses the 'isoUtcDateTime' mask to format the current date in ISO UTC format.

const dateFormat = require('dateformat');
const now = new Date();
dateFormat(now, 'isoUtcDateTime');

Custom date formatting

Users can create custom date formats using the formatting tokens provided by the package. The code sample formats the current time using a custom format for hours, minutes, and seconds.

const dateFormat = require('dateformat');
const now = new Date();
dateFormat(now, 'HH:MM:ss');

Other packages similar to dateformat

moment

Moment.js is a popular date manipulation library that offers a wide range of date formatting options. It is more feature-rich than dateformat, providing extensive support for date parsing, manipulation, and localization. However, it is larger in size and has been considered a legacy project in maintenance mode since 2020.

dayjs

Day.js is a lightweight date formatting and manipulation library that offers a similar API to Moment.js. It is more modern and modular, allowing users to load only the plugins they need. Day.js is a good alternative to dateformat when additional date manipulation capabilities are required.

date-fns

Date-fns is a modular date utility library that provides the most comprehensive set of date formatting and manipulation functions. It is designed to be modular, so you can pick and choose which functions you need, resulting in smaller bundle sizes. It is a strong alternative to dateformat for projects that require both formatting and complex date logic.

README

dateformat

A node.js package for Steven Levithan's excellent dateFormat() function.

Modifications

• Removed the Date.prototype.format method. Sorry folks, but extending native prototypes is for suckers.
• Added a module.exports = dateFormat; statement at the bottom
• Added the placeholder N to get the ISO 8601 numeric representation of the day of the week

Installation

$ npm install dateformat
$ dateformat --help

Usage

As taken from Steven's post, modified to match the Modifications listed above:

var dateFormat = require('dateformat');
var now = new Date();

// Basic usage
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
dateFormat(now, "isoDateTime");
// 2007-06-09T17:46:21

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

// 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
dateFormat(now);
// 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. Simply pass in
// true as an additional argument (no argument skipping allowed in this case):
dateFormat(now, "longTime", true);
// 10:46:21 PM UTC

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

// You can also get the ISO 8601 week of the year:
dateFormat(now, "W");
// 42

// and also get the ISO 8601 numeric representation of the day of the week:
dateFormat(now,"N");
// 6

Mask options

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.
N	ISO 8601 numeric representation of the day of the week.
o	GMT/UTC timezone offset, e.g. -0500 or +0230.
s	Seconds; no leading zero for single-digit seconds.
ss	Seconds; leading zero for single-digit seconds.
S	The date's ordinal suffix (st, nd, rd, or th). Works well with d.
l	Milliseconds; gives 3 digits.
L	Milliseconds; 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.
W	ISO 8601 week number of the year, e.g. 42
Z	US timezone abbreviation, e.g. EST or MDT. With non-US timezones or in the
'...', "..."	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.

Named Formats

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

Localization

Day names, month names and the AM/PM indicators can be localized by passing an object with the necessary strings. For example:

var dateFormat = require('dateformat');
dateFormat.i18n = {
    dayNames: [
        'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat',
        'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'
    ],
    monthNames: [
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
        'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'
    ],
    timeNames: [
        'a', 'p', 'am', 'pm', 'A', 'P', 'AM', 'PM'
    ]
};

Notice that only one language is supported at a time and all strings must be present in the new value.

Breaking change in 2.1.0

• 2.1.0 was published with a breaking change, for those using localized strings.
• 2.2.0 has been published without the change, to keep packages refering to ^2.0.0 to continue working. This is now branch v2_2.
• 3.0.* contains the localized AM/PM change.

License

(c) 2007-2009 Steven Levithan stevenlevithan.com, MIT license.