Intl.Collator.prototype.compare()

const enCollator = new Intl.Collator("en");
const deCollator = new Intl.Collator("de");
const svCollator = new Intl.Collator("sv");
console.log(enCollator.compare("z", "a") > 0);
// Expected output: true
console.log(deCollator.compare("z", "ä") > 0);
// Expected output: true
console.log(svCollator.compare("z", "ä") > 0);
// Expected output: false

compare(string1, string2);

var a = ["Offenbach", "Österreich", "Odenwald"];
var collator = new Intl.Collator("de-u-co-phonebk");
a.sort(collator.compare);
console.log(a.join(", "));
// → "Odenwald, Österreich, Offenbach"

var a = ["Congrès", "congres", "Assemblée", "poisson"];
var collator = new Intl.Collator("fr", {
  usage: "search",
  sensitivity: "base",
});
var s = "congres";
var matches = a.filter((v) => collator.compare(v, s) === 0);
console.log(matches.join(", "));
// → "Congrès, congres"