date-and-time

This library is a minimalist collection of functions for manipulating JS date and time. It's tiny, simple, easy to learn.

Why

JS modules nowadays are getting more huge and complex, and there are also many dependencies. Trying to keep each module simple and small is meaningful.

Features

• Minimalist. Less than 2k. (minified and gzipped)
• Extensible. Plugin system support.
• Multi language support.
• Universal / Isomorphic. Wherever JS runtime works.
• Older browser support. Even works on IE6. :)

Install

• via npm:

npm install date-and-time --save

• local:

<script src="/path/to/date-and-time.min.js"></script>

Recent Changes

• 0.11.0

  • Added a compile() function that precompiling a date string for the parser. In case of processing many date string with one format, by using this function, you could be able to get results faster than before.

  // We have passed a string format at the 2nd parameter every time when calling the parse() function.
  date.parse('Mar. 22 2019 2:54:21 p.m.', 'MMM. D YYYY h:m:s A');
  date.parse('Jul. 27 2019 4:15:24 a.m.', 'MMM. D YYYY h:m:s A');
  date.parse('Dec. 25 2019 3:51:11 a.m.', 'MMM. D YYYY h:m:s A');
  
  // You can precompile the string format.
  const pattern = date.compile('MMM. D YYYY h:m:s A');
  
  // The parse() will be able to finish faster than passing the format string every time.
  date.parse('Mar. 22 2019 2:54:21 p.m.', pattern);
  date.parse('Jul. 27 2019 4:15:24 a.m.', pattern);
  date.parse('Dec. 25 2019 3:51:11 a.m.', pattern);

  const pattern = date.compile('MMM. D YYYY h:m:s A');
  
  // The isValid() will also too.
  date.isValid('Mar. 22 2019 2:54:21 p.m.', pattern);

• 0.10.0

  • The YYYY token has come to require 4 digits in the parse(), the preparse() and the isValid() (Breaking Change).

  date.parse('31-12-0123', 'DD-MM-YYYY');   // Good
  date.parse('31-12-123', 'DD-MM-YYYY');    // Not good

  • The YY token has come to require 2 digits in the above functions (Breaking Change).

  date.parse('31-12-03', 'DD-MM-YY');   // Good, but It's interpreted the year is 2003.
  date.parse('31-12-3', 'DD-MM-YY');    // Not good

  • Added a Y token to support year, 4 or less digits in the above functions. This new token, Y is equivalent to the previous YYYY token.

  date.parse('31-12-123', 'DD-MM-Y');   // Good
  date.parse('31-12-3', 'DD-MM-Y');     // Good

• 0.9.0 (Locale Update)

  • Renewal of the locale system. Some functions were merged (Breaking Change).
  • Added a plugin system. You could extend a formatter and a parser by using this mechanism.
  • With the addition of the plugin system, the format() has come to accept a user original token.

• 0.8.0 (Parser Update)

  • The parse() has come to return Invalid Date instead of NaN when parsing is failure (Breaking Change).
  • Added preparse(). It returns a Date Structure.
  • The isValid() has come to take a Date Structure in addition to a date string.
  • The isLeapYear() has come to take a year (number type) instead of a Date object (Breaking Change).

Usage

• Node.js:

const date = require('date-and-time');

• With a transpiler:

import date from 'date-and-time';

• With an older browser:

window.date;    // global object

API

format(dateObj, formatString[, utc])

• Formatting a date.
  • @param {Date} dateObj - a Date object
  • @param {string} formatString - a format string
  • @param {boolean} [utc] - output as UTC
  • @returns {string} a formatted string

const now = new Date();
date.format(now, 'YYYY/MM/DD HH:mm:ss');    // => '2015/01/02 23:14:05'
date.format(now, 'ddd., MMM. DD YYYY');     // => 'Fri., Jan. 02 2015'
date.format(now, 'hh:mm A [GMT]Z');         // => '11:14 p.m. GMT-0800'
date.format(now, 'hh:mm A [GMT]Z', true);   // => '07:14 a.m. GMT+0000'

Available tokens and their meanings are as follows:

token	meaning	example
YYYY	year	0999, 2015
YY	year	05, 99
Y	year	2, 44, 888, 2015
MMMM	month	January, December
MMM	month	Jan, Dec
MM	month	01, 12
M	month	1, 12
DDD (*)	day	1st, 2nd, 3rd
DD	day	02, 31
D	day	2, 31
dddd	day of week	Friday, Sunday
ddd	day of week	Fri, Sun
dd	day of week	Fr, Su
HH	24-hour	23, 08
H	24-hour	23, 8
A	meridiem	a.m., p.m.
a (*)	meridiem	A.M., P.M.
AA (*)	meridiem	AM, PM
aa (*)	meridiem	am, pm
hh	12-hour	11, 08
h	12-hour	11, 8
mm	minute	14, 07
m	minute	14, 7
ss	second	05, 10
s	second	5, 10
SSS	millisecond	753, 022
SS	millisecond	75, 02
S	millisecond	7, 0
Z	timezone	+0100, -0800

(*) Not available by default. See PLUGINS.md for details.

NOTE 1. Comments

Strings in parenthese [...] in the formatString will be ignored as comments:

date.format(new Date(), 'DD-[MM]-YYYY');    // => '02-MM-2015'
date.format(new Date(), '[DD-[MM]-YYYY]');  // => 'DD-[MM]-YYYY'

NOTE 2. Output as UTC

This function usually outputs a local date-time string. Set to true a utc option (the 3rd parameter) if you would like to get a UTC date/time string.

date.format(new Date(), 'hh:mm A [GMT]Z');          // => '11:14 p.m. GMT-0800'
date.format(new Date(), 'hh:mm A [GMT]Z', true);    // => '07:14 a.m. GMT+0000'

NOTE 3. More Tokens

You could also define your own tokens. See PLUGINS.md for details.

---

compile(formatString)

• Compiling a format string for the parser.
  • @param {string} formatString - a format string
  • @returns {Array.<string>} a compiled object

  const pattern = date.compile('MMM. D YYYY h:m:s A');

  date.parse('Mar. 22 2019 2:54:21 p.m.', pattern);
  date.parse('Jul. 27 2019 4:15:24 a.m.', pattern);
  date.parse('Dec. 25 2019 3:51:11 a.m.', pattern);

If you are going to call the parse() or the isValid() many times with one string format, recommended to precompile and reuse it for performance.

---

parse(dateString, arg[, utc])

• Parsing a date string.
  • @param {string} dateString - a date string
  • @param {string|Array.<string>} arg - a format string or a compiled object
  • @param {boolean} [utc] - input as UTC
  • @returns {Date} a constructed date

date.parse('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss');   // => Jan. 2 2015 23:14:05 GMT-0800
date.parse('02-01-2015', 'DD-MM-YYYY');                     // => Jan. 2 2015 00:00:00 GMT-0800
date.parse('11:14:05 p.m.', 'hh:mm:ss A');                  // => Jan. 1 1970 23:14:05 GMT-0800
date.parse('11:14:05 p.m.', 'hh:mm:ss A', true);            // => Jan. 1 1970 15:14:05 GMT-0800
date.parse('Jam. 1 2017', 'MMM. D YYYY');                   // => Invalid Date
date.parse('Feb. 29 2016', 'MMM. D YYYY');                  // => Feb. 29 2016 00:00:00 GMT-0800
date.parse('Feb. 29 2017', 'MMM. D YYYY');                  // => Invalid Date

Available tokens and their meanings are as follows:

token	meaning	example
YYYY	year	0999, 2015
YY	year	05, 99
Y	year	2, 44, 88, 2015
MMMM	month	January, December
MMM	month	Jan, Dec
MM	month	01, 12
M	month	1, 12
DD	day	02, 31
D	day	2, 31
HH	24-hour	23, 08
H	24-hour	23, 8
hh	12-hour	11, 08
h	12-hour	11, 8
A	meridiem	a.m., p.m.
A (*)	meridiem	A.M., P.M.
A (*)	meridiem	AM, PM
A (*)	meridiem	am, pm
mm	minute	14, 07
m	minute	14, 7
ss	second	05, 10
s	second	5, 10
SSS	millisecond	753, 022
SS	millisecond	75, 02
S	millisecond	7, 0

(*) Not available by default. See PLUGINS.md for details.

NOTE 1. Invalid Date

If the function fails to parse, it will return Invalid Date. Notice that the Invalid Date is a Date object, not NaN or null. You could tell whether the Date object is invalid as follows:

const today = date.parse('Jam. 1 2017', 'MMM. D YYYY');

if (isNaN(today)) {
    // Failure
}

NOTE 2. Input as UTC

This function usually assumes the dateString is local date-time. Set to true a utc option (the 3rd parameter) if it is UTC.

date.parse('11:14:05 p.m.', 'hh:mm:ss A');          // => Jan. 1 1970 23:14:05 GMT-0800
date.parse('11:14:05 p.m.', 'hh:mm:ss A', true);    // => Jan. 1 1970 15:14:05 GMT-0800

NOTE 3. Default Date Time

Default date is January 1, 1970, time is 00:00:00.000. Values not passed will be complemented with them:

date.parse('11:14:05 p.m.', 'hh:mm:ss A');  // => Jan. 1 1970 23:14:05 GMT-0800
date.parse('Feb. 2000', 'MMM. YYYY');       // => Feb. 1 2000 00:00:00 GMT-0800

NOTE 4. Max Date / Min Date

Parsable maximum date is December 31, 9999, minimum date is January 1, 0001.

date.parse('Dec. 31 9999', 'MMM. D YYYY');  // => Dec. 31 9999 00:00:00 GMT-0800
date.parse('Dec. 31 10000', 'MMM. D YYYY'); // => Invalid Date

date.parse('Jan. 1 0001', 'MMM. D YYYY');   // => Jan. 1 0001 00:00:00 GMT-0800
date.parse('Jan. 1 0000', 'MMM. D YYYY');   // => Invalid Date

NOTE 5. Auto Mapping

The YY token maps the year 69 or less to the 2000s, the year 70 or more to the 1900s. Using it is not recommended.

date.parse('Dec. 31 00', 'MMM. D YY');  // => Dec. 31 2000 00:00:00 GMT-0800
date.parse('Dec. 31 69', 'MMM. D YY');  // => Dec. 31 2069 00:00:00 GMT-0800
date.parse('Dec. 31 70', 'MMM. D YY');  // => Dec. 31 1970 00:00:00 GMT-0800
date.parse('Dec. 31 99', 'MMM. D YY');  // => Dec. 31 1999 00:00:00 GMT-0800

NOTE 6. 12-hour notation and Meridiem

If use the hh or h (12-hour) token, use together the A (meridiem) token to get the right value.

date.parse('11:14:05', 'hh:mm:ss');         // => Jan. 1 1970 11:14:05 GMT-0800
date.parse('11:14:05 p.m.', 'hh:mm:ss A');  // => Jan. 1 1970 23:14:05 GMT-0800

NOTE 7. Comments

Strings in parenthese [...] in the formatString will be ignored as comments:

date.parse('12 hours 34 minutes', 'HH hours mm minutes');       // => Invalid Date
date.parse('12 hours 34 minutes', 'HH [hours] mm [minutes]');   // => Jan. 1 1970 12:34:00 GMT-0800

As a white space works as a wild card, you could also write as follows:

date.parse('12 hours 34 minutes', 'HH       mm        ');   // => Jan. 1 1970 12:34:00 GMT-0800

---

preparse(dateString, arg)

• Pre-parsing a date string.
  • @param {string} dateString - a date string
  • @param {string|Array.<string>} arg - a format string or a compiled object
  • @returns {Object} a date structure

This function takes exactly the same parameters with the parse(), but returns a date structure as follows unlike it:

date.preparse('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss');

{
    Y: 2015,        // Year
    M: 1,           // Month
    D: 2,           // Day
    H: 23,          // 24-hour
    A: 0,           // Meridiem
    h: 0,           // 12-hour
    m: 14,          // Minute
    s: 5,           // Second
    S: 0,           // Millisecond
    _index: 19,     // Pointer offset
    _length: 19,    // Length of the date string
    _match: 6       // Token matching count
}

This object shows a parsing result. You would be able to tell from it how the date string was parsed(, or why the parsing was failed).

---

isValid(arg1[, arg2])

• Validation.
  • @param {Object|string} arg1 - a date structure or a date string
  • @param {string|Array.<string>} [arg2] - a format string or a compiled object
  • @returns {boolean} whether the date string is a valid date

This function takes either exactly the same parameters with the parse() or a date structure which the preparse() returns, evaluates the validity of them.

date.isValid('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss'); // => true
date.isValid('29-02-2015', 'DD-MM-YYYY');                   // => false

const result = date.preparse('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss');
date.isValid(result);   // => true

---

addYears(dateObj, years)

• Adding years.
  • @param {Date} dateObj - a Date object
  • @param {number} years - number of years to add
  • @returns {Date} a date after adding the value

const now = new Date();
const next_year = date.addYears(now, 1);

---

addMonths(dateObj, months)

• Adding months.
  • @param {Date} dateObj - a Date object
  • @param {number} months - number of months to add
  • @returns {Date} a date after adding the value

const now = new Date();
const next_month = date.addMonths(now, 1);

---

addDays(dateObj, days)

• Adding days.
  • @param {Date} dateObj - a Date object
  • @param {number} days - number of days to add
  • @returns {Date} a date after adding the value

const now = new Date();
const yesterday = date.addDays(now, -1);

---

addHours(dateObj, hours)

• Adding hours.
  • @param {Date} dateObj - a Date object
  • @param {number} hours - number of hours to add
  • @returns {Date} a date after adding the value

const now = new Date();
const an_hour_ago = date.addHours(now, -1);

---

addMinutes(dateObj, minutes)

• Adding minutes.
  • @param {Date} dateObj - a Date object
  • @param {number} minutes - number of minutes to add
  • @returns {Date} a date after adding the value

const now = new Date();
const two_minutes_later = date.addMinutes(now, 2);

---

addSeconds(dateObj, seconds)

• Adding seconds.
  • @param {Date} dateObj - a Date object
  • @param {number} seconds - number of seconds to add
  • @returns {Date} a date after adding the value

const now = new Date();
const three_seconds_ago = date.addSeconds(now, -3);

---

addMilliseconds(dateObj, milliseconds)

• Adding milliseconds.
  • @param {Date} dateObj - a Date object
  • @param {number} milliseconds - number of milliseconds to add
  • @returns {Date} a date after adding the value

const now = new Date();
const a_millisecond_later = date.addMilliseconds(now, 1);

---

subtract(date1, date2)

• Subtracting.
  • @param {Date} date1 - a Date object
  • @param {Date} date2 - a Date object
  • @returns {Object} a result object subtracting date2 from date1

const today = new Date(2015, 0, 2);
const yesterday = new Date(2015, 0, 1);

date.subtract(today, yesterday).toDays();           // => 1 = today - yesterday
date.subtract(today, yesterday).toHours();          // => 24
date.subtract(today, yesterday).toMinutes();        // => 1440
date.subtract(today, yesterday).toSeconds();        // => 86400
date.subtract(today, yesterday).toMilliseconds();   // => 86400000

---

isLeapYear(y)

• Leap year.
  • @param {number} y - year
  • @returns {boolean} whether the year is a leap year

date.isLeapYear(2015);  // => false
date.isLeapYear(2012);  // => true

---

isSameDay(date1, date2)

• Comparison of two dates.
  • @param {Date} date1 - a Date object
  • @param {Date} date2 - a Date object
  • @returns {boolean} whether the dates are the same day (times are ignored)

const date1 = new Date(2017, 0, 2, 0);          // Jan. 2 2017 00:00:00
const date2 = new Date(2017, 0, 2, 23, 59);     // Jan. 2 2017 23:59:00
const date3 = new Date(2017, 0, 1, 23, 59);     // Jan. 1 2017 23:59:00
date.isSameDay(date1, date2);   // => true
date.isSameDay(date1, date3);   // => false

---

locale([code[, locale]])

• Change locale or setting a new locale definition.
  • @param {string} [code] - language code
  • @param {Object} [locale] - locale definition
  • @returns {string} current language code

Returns current language code if called without any parameters.

date.locale();  // "en"

To switch to any other language, call it with a language code.

date.locale('es');  // Switch to Spanish

To define a new locale, call it with new language code and a locale definition. See LOCALE.md for details.

---

extend(extension)

• Locale extension.
  • @param {Object} extension - locale definition
  • @returns {void}

Extends a current locale (formatter and parser). See PLUGINS.md for details.

---

plugin(name[, extension])

• Plugin import or definition.
  • @param {string} name - plugin name
  • @param {Object} [extension] - locale definition
  • @returns {void}

Plugin is a named locale definition defined with the extend(). See PLUGINS.md for details.

---

Browser Support

Chrome, Firefox, Safari, Edge, and Internet Explorer 6+.

License

MIT