Intl.Locale.prototype.minimize()

const english = new Intl.Locale("en-Latn-US");
const korean = new Intl.Locale("ko-Kore-KR");
const arabic = new Intl.Locale("ar-Arab-EG");

console.log(english.minimize().baseName);
// Expected output: "en"

console.log(korean.minimize().baseName);
// Expected output: "ko"

console.log(arabic.minimize().baseName);
// Expected output: "ar"

minimize()

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

const myLocMinimized = myLocale.minimize();

// Prints "fr", since French is only written in the Latin script
// and is most likely to be spoken in France.
console.log(myLocMinimized.baseName);

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