with-ordinal-suffix.js

const ordinalSuffixes = {
    "one": "st",
    "two": "nd",
    "few": "rd",
    "other": "th"
};

const ordinalPluralRules = new Intl.PluralRules("en", { type: "ordinal" });

function withOrdinalSuffix(x) {
    if(typeof x != "number") throw new TypeError(`Expected Number but received ${typeof x}`);
    if(x < 1) throw new RangeError(`Expected a number > 0 but received ${x}`);
    const ordinal = ordinalPluralRules.select(x);
    if (!ordinal in ordinalSuffixes) throw new Error(`Unexpected ordinal ${ordinal}`);
    const suffix = ordinalSuffixes[ordinal];
    return `${x}${suffix}`;
}

withOrdinalSuffix(28) // 28th
withOrdinalSuffix(1) // 1st
withOrdinalSuffix(2) // 2nd
withOrdinalSuffix(3) // 3rd
withOrdinalSuffix(4) // 4th
withOrdinalSuffix(5) // 5th