Web/JavaScript/Reference/Global objects/Intl/DateTimeFormat/supportedLocalesOf

From Get docs


The Intl.DateTimeFormat.supportedLocalesOf() method returns an array containing those of the provided locales that are supported in date and time formatting without having to fall back to the runtime's default locale.


The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

Intl.DateTimeFormat.supportedLocalesOf(locales[, options])

Parameters

locales
A string with a BCP 47 language tag, or an array of such strings. For the general form of the locales argument, see the Intl page.
options
Optional. An object that may have the following property:
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.

Return value

An array of strings representing a subset of the given locale tags that are supported in date and time formatting without having to fall back to the runtime's default locale.

Description

Returns an array with a subset of the language tags provided in locales. The language tags returned are those for which the runtime supports a locale in date and time formatting that the locale matching algorithm used considers a match, so that it wouldn't have to fall back to the default locale.

Examples

Using supportedLocalesOf

Assuming a runtime that supports Indonesian and German but not Balinese in date and time formatting, supportedLocalesOf returns the Indonesian and German language tags unchanged, even though pinyin collation is neither relevant to date and time formatting nor used with Indonesian, and a specialized German for Indonesia is unlikely to be supported. Note the specification of the "lookup" algorithm here — a "best fit" matcher might decide that Indonesian is an adequate match for Balinese since most Balinese speakers also understand Indonesian, and therefore return the Balinese language tag as well.

var locales = ['ban', 'id-u-co-pinyin', 'de-ID'];
var options = { localeMatcher: 'lookup' };
console.log(Intl.DateTimeFormat.supportedLocalesOf(locales, options).join(', '));
// → "id-u-co-pinyin, de-ID"

Specifications

Specification
ECMAScript Internationalization API (ECMA-402)The definition of 'Intl.DateTimeFormat.supportedLocalesOf' in that specification.

Browser compatibility

Update compatibility data on GitHub

Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet Node.js
supportedLocalesOf Chrome

Full support 24

Edge

Full support 12

Firefox

Full support 29

IE

Full support 11

Opera

Full support 15

Safari

Full support 10

WebView Android

Full support 4.4

Chrome Android

Full support 25

Firefox Android

Full support 56

Opera Android

Full support 14

Safari iOS

Full support 10

Samsung Internet Android

Full support 1.5

nodejs Full support 13.0.0


Full support 13.0.0


Partial support 0.12

Notes'

Notes' Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available for versions prior to 13, see Node.js documentation on the --with-intl option and how to provide the data.

Legend

Full support  
Full support
See implementation notes.'
See implementation notes.


See also