Word segmentation with pure V8 engine.

segmentger.js

let segment = (text) => {
    let it = Intl.v8BreakIterator('ja');
    it.adoptText(text);
    let result = [];
    let curr, next;
    while (true) {
        curr = it.current();
        next = it.next();
        if (next == -1) break;
        result.push(text.slice(curr, next));
    }
    return result;
}