exercism-ts/acronym/acronym.ts

export function parse(phrase: string): string {
    const rxUp = /\p{Lu}/u;
    if (phrase === "") {
        return "";
    }
    let sub = "";
    const words = phrase.split(/[^\w]/)
    for (let word of words) {
        if (word === "") {
            continue;
        }
        const initial = word.substring(0, 1);
        sub += initial.toUpperCase();
        let inUpGroup = rxUp.test(initial);
        for (let i = 1; i < word.length; i++) {
            const c = word.charAt(i);
            if (rxUp.test(c)) {
                if (inUpGroup) {
                    continue;
                }
                sub += c;
                continue;
            }
            inUpGroup = false;
        }
    }
    return sub;
}