Intl.Segmenter.prototype.segment()

segment(input)

// Create a locale-specific word segmenter
const segmenter = new Intl.Segmenter("fr", {granularity: "word"});

// Use it to get an iterator over the segments of a string
const input = "Moi ? N'est-ce pas ?";
const segments = segmenter.segment(input);

// Use that for segmentation
for (const {segment, index, isWordLike} of segments) {
  console.log("segment at code units [%d, %d]: «%s»%s",
    index, index + segment.length,
    segment,
    isWordLike ? " (word-like)" : ""
  );
}
// segment at code units [0, 3]: «Moi» (word-like)
// segment at code units [3, 4]: « »
// segment at code units [4, 5]: «?»
// segment at code units [5, 6]: « »
// segment at code units [6, 11]: «N'est» (word-like)
// segment at code units [11, 12]: «-»
// segment at code units [12, 14]: «ce» (word-like)
// segment at code units [14, 15]: « »
// segment at code units [15, 18]: «pas» (word-like)
// segment at code units [18, 19]: « »
// segment at code units [19, 20]: «?»