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.
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"
}Intl.getCanonicalLocales(locales)localesA list of String values for which to get the canonical locale names.
An array containing the canonical locale names.
Intl.getCanonicalLocales("EN-US"); // ["en-US"]
Intl.getCanonicalLocales(["EN-US", "Fr"]); // ["en-US", "fr"]
Intl.getCanonicalLocales("EN_US");
// RangeError: invalid language tag: "EN_US"