Intl.Locale.prototype.maximize()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2020.

The maximize() method of Intl.Locale instances gets the most likely values for the language, script, and region of this locale based on existing values.

Try it

const english = new Intl.Locale("en");
const korean = new Intl.Locale("ko");
const arabic = new Intl.Locale("ar");

console.log(english.maximize().baseName);
// Expected output: "en-Latn-US"

console.log(korean.maximize().baseName);
// Expected output: "ko-Kore-KR"

console.log(arabic.maximize().baseName);
// Expected output: "ar-Arab-EG"

Syntax

js
maximize()

Parameters

None.

Return value

A Intl.Locale instance whose baseName property returns the result of the Add Likely Subtags algorithm executed against locale.baseName.

Description

Sometimes, it is convenient to be able to identify the most likely locale language identifier subtags based on an incomplete language ID. The Add Likely Subtags algorithm gives us this functionality. For instance, given the language ID "en", the algorithm would return "en-Latn-US", since English can only be written in the Latin script, and is most likely to be used in the United States, as it is the largest English-speaking country in the world. This functionality is provided to JavaScript programmers via the maximize() method. maximize() only affects the main subtags that comprise the language identifier: language, script, and region subtags. Other subtags after the "-u" in the locale identifier are called extension subtags and are not affected by the maximize() method. Examples of these subtags include hourCycle, calendar, and numeric.

Examples

Using maximize

js
const myLocale = new Intl.Locale("fr", {
  hourCycle: "h12",
  calendar: "gregory",
});
console.log(myLocale.baseName); // Prints "fr"
console.log(myLocale.toString()); // Prints "fr-u-ca-gregory-hc-h12"
const myLocMaximized = myLocale.maximize();

// Prints "fr-Latn-FR". The "Latn" and "FR" tags are added,
// since French is only written in the Latin script and is most likely to be spoken in France.
console.log(myLocMaximized.baseName);

// Prints "fr-Latn-FR-u-ca-gregory-hc-h12".
// Note that the extension tags (after "-u") remain unchanged.
console.log(myLocMaximized.toString());

Specifications

Specification
ECMAScript® 2025 Internationalization API Specification
# sec-Intl.Locale.prototype.maximize

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
maximize

Legend

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Full support
Full support

See also