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Intl.getCanonicalLocales()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨October 2017⁩.

The Intl.getCanonicalLocales() static method returns an array containing the canonical locale names. Duplicates will be omitted and elements will be validated as structurally valid language tags.

Try it

console.log(Intl.getCanonicalLocales("EN-US"));
// Expected output: Array ["en-US"]

console.log(Intl.getCanonicalLocales(["EN-US", "Fr"]));
// Expected output: Array ["en-US", "fr"]

try {
  Intl.getCanonicalLocales("EN_US");
} catch (err) {
  console.log(err.toString());
  // Expected output: RangeError: invalid language tag: "EN_US"
}

Syntax

Intl.getCanonicalLocales(locales)

Parameters

locales: A list of String values for which to get the canonical locale names.

Return value

An array containing the canonical locale names.

Examples

Using getCanonicalLocales

Intl.getCanonicalLocales("EN-US"); // ["en-US"]
Intl.getCanonicalLocales(["EN-US", "Fr"]); // ["en-US", "fr"]

Intl.getCanonicalLocales("EN_US");
// RangeError: invalid language tag: "EN_US"

Specifications

Specification
ECMAScript® 2026 Internationalization API Specification> # sec-intl.getcanonicallocales>

Browser compatibility

	Desktop					Mobile							Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`getCanonicalLocales`	54	16	48	41	10.1	54	56	41	10.3	6.0	54	10.3	1.0.0	1.8	7.0.0