Intl.DateTimeFormat

The Intl.DateTimeFormat object is a constructor for objects that enable language-sensitive date and time formatting.

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Syntax

new Intl.DateTimeFormat([locales[, options]])
Intl.DateTimeFormat.call(this[, locales[, options]])

Parameters

locales

Optional. A string with a BCP 47 language tag, or an array of such strings. To choose the browser's default locale, use "default". Unicode extension are supported (for example "en-US-u-ca-buddhist"). For the general form and interpretation of the locales argument, see the Intl page. The following Unicode extension keys are allowed:

nu

Numbering system. Possible values include: "arab", "arabext", "bali", "beng", "deva", "fullwide", "gujr", "guru", "hanidec", "khmr", "knda", "laoo", "latn", "limb", "mlym", "mong", "mymr", "orya", "tamldec", "telu", "thai", "tibt".

ca

Calendar. Possible values include: "buddhist", "chinese", "coptic", "ethiopia", "ethiopic", "gregory", "hebrew", "indian", "islamic", "islamic", "iso8601", "japanese", "persian", "roc".

hc

Hour cycle. Possible values include: "h11", "h12", "h23", "h24".

options

Optional. An object with some or all of the following properties:

localeMatcher

The locale matching algorithm to use. Possible values are "lookup" and "best fit"; the default is "best fit". For information about this option, see the Intl page.

timeZone

The time zone to use. The only value implementations must recognize is "UTC"; the default is the runtime's default time zone. Implementations may also recognize the time zone names of the IANA time zone database, such as "Asia/Shanghai", "Asia/Kolkata", "America/New_York".

hour12

Whether to use 12-hour time (as opposed to 24-hour time). Possible values are true and false; the default is locale dependent. This option overrides the hc language tag and/or the hourCycle option in case both are present.

hourCycle

The hour cycle to use. Possible values are "h11", "h12", "h23", or "h24". This option overrides the hc language tag, if both are present, and the hour12 option takes precedence in case both options have been specified.

formatMatcher

The format matching algorithm to use. Possible values are "basic" and "best fit"; the default is "best fit". See the following paragraphs for information about the use of this property.

The following properties describe the date-time components to use in formatted output, and their desired representations. Implementations are required to support at least the following subsets:

• weekday, year, month, day, hour, minute, second
• weekday, year, month, day
• year, month, day
• year, month
• month, day
• hour, minute, second
• hour, minute

Implementations may support other subsets, and requests will be negotiated against all available subset-representation combinations to find the best match. Two algorithms are available for this negotiation and selected by the formatMatcher property: A fully specified "basic" algorithm and an implementation-dependent "best fit" algorithm.

weekday

The representation of the weekday. Possible values are:

• "long" (e.g., Thursday)
• "short" (e.g., Thu)
• "narrow" (e.g., T). Two weekdays may have the same narrow style for some locales (e.g. Tuesday's narrow style is also T).

era

The representation of the era. Possible values are:

• "long" (e.g., Anno Domini)
• "short" (e.g., AD)
• "narrow" (e.g., A)

year

The representation of the year. Possible values are:

• "numeric" (e.g., 2012)
• "2-digit" (e.g., 12)

month

The representation of the month. Possible values are:

• "numeric" (e.g., 2)
• "2-digit" (e.g., 02)
• "long" (e.g., March)
• "short" (e.g., Mar)
• "narrow" (e.g., M). Two months may have the same narrow style for some locales (e.g. May's narrow style is also M).

day

The representation of the day. Possible values are:

• "numeric" (e.g., 1)
• "2-digit" (e.g., 01)

hour

The representation of the hour. Possible values are "numeric", "2-digit".

minute

The representation of the minute. Possible values are "numeric", "2-digit".

second

The representation of the second. Possible values are "numeric", "2-digit".

timeZoneName

The representation of the time zone name. Possible values are:

• "long" (e.g., British Summer Time)
• "short" (e.g., GMT+1)

The default value for each date-time component property is undefined, but if all component properties are undefined, then year, month, and day are assumed to be "numeric".

Description

Properties

Intl.DateTimeFormat.prototype

Allows the addition of properties to all objects.

Methods

Intl.DateTimeFormat.supportedLocalesOf()

Returns an array containing those of the provided locales that are supported without having to fall back to the runtime's default locale.

DateTimeFormat instances

Properties

DateTimeFormat instances inherit the following properties from their prototype:

Methods

DateTimeFormat instances inherit the following methods from their prototype:

Examples

Using DateTimeFormat

In basic use without specifying a locale, DateTimeFormat uses the default locale and default options.

var date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// toLocaleString without arguments depends on the implementation,
// the default locale, and the default time zone
console.log(new Intl.DateTimeFormat().format(date));
// → "12/19/2012" if run with en-US locale (language) and time zone America/Los_Angeles (UTC-0800)

Using locales

This example shows some of the variations in localized date and time formats. In order to get the format of the language used in the user interface of your application, make sure to specify that language (and possibly some fallback languages) using the locales argument:

var date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// Results below use the time zone of America/Los_Angeles (UTC-0800, Pacific Standard Time)

// US English uses month-day-year order
console.log(new Intl.DateTimeFormat('en-US').format(date));
// → "12/19/2012"

// British English uses day-month-year order
console.log(new Intl.DateTimeFormat('en-GB').format(date));
// → "19/12/2012"

// Korean uses year-month-day order
console.log(new Intl.DateTimeFormat('ko-KR').format(date));
// → "2012. 12. 19."

// Arabic in most Arabic speaking countries uses real Arabic digits
console.log(new Intl.DateTimeFormat('ar-EG').format(date));
// → "١٩‏/١٢‏/٢٠١٢"

// for Japanese, applications may want to use the Japanese calendar,
// where 2012 was the year 24 of the Heisei era
console.log(new Intl.DateTimeFormat('ja-JP-u-ca-japanese').format(date));
// → "24/12/19"

// when requesting a language that may not be supported, such as
// Balinese, include a fallback language, in this case Indonesian
console.log(new Intl.DateTimeFormat(['ban', 'id']).format(date));
// → "19/12/2012"

Using options

The date and time formats can be customized using the options argument:

var date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// request a weekday along with a long date
var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
console.log(new Intl.DateTimeFormat('de-DE', options).format(date));
// → "Donnerstag, 20. Dezember 2012"

// an application may want to use UTC and make that visible
options.timeZone = 'UTC';
options.timeZoneName = 'short';
console.log(new Intl.DateTimeFormat('en-US', options).format(date));
// → "Thursday, December 20, 2012, GMT"

// sometimes you want to be more precise
options = {
  hour: 'numeric', minute: 'numeric', second: 'numeric', 
  timeZone: 'Australia/Sydney',
  timeZoneName: 'short'
};
console.log(new Intl.DateTimeFormat('en-AU', options).format(date));
// → "2:00:00 pm AEDT"

// sometimes even the US needs 24-hour time
options = {
  year: 'numeric', month: 'numeric', day: 'numeric',
  hour: 'numeric', minute: 'numeric', second: 'numeric',
  hour12: false,
  timeZone: 'America/Los_Angeles' 
};
console.log(new Intl.DateTimeFormat('en-US', options).format(date));
// → "12/19/2012, 19:00:00"

// to specify options but use the browser's default locale, use 'default'
console.log(new Intl.DateTimeFormat('default', options).format(date));
// → "12/19/2012, 19:00:00"

Specifications

Browser compatibility

See also