use Intl.Segmenter

topWords.js

function topWords(text, count = 3, lang = 'en') {
  const wordMap = new Map();
  const segmenter = new Intl.Segmenter(lang, { granularity: 'word' });
  for (let { segment, index, isWordLike } of segmenter.segment(text)) {
    if (!isWordLike) continue;
    const word = segment;
    wordMap.set(word, (wordMap.get(word) || 0) + 1);
  }
  return Array.from(wordMap)
    .sort(([, countA], [, countB]) => countB - countA)
    .slice(0, count)
    .map(([word]) => word);
}