How to use the google-play-scraper.reviews function in google-play-scraper

function reviews() {
  var app = APPS[currentIndex];
  incrementIndex(APPS.length);

  var request = gplay.reviews({
    appId: app.package,
    page: 0,
    sort: gplay.sort.NEWEST
  });
  return request.then(toRuleResult(app));
}

const subpath = '/apps/' + req.params.appId + '/reviews/';
    if (page > 0) {
      req.query.page = page - 1;
      apps.prev = buildUrl(req, subpath) + '?' + qs.stringify(req.query);
    }

    if (apps.results.length) {
      req.query.page = page + 1;
      apps.next = buildUrl(req, subpath) + '?' + qs.stringify(req.query);
    }

    return apps;
  }

  const opts = Object.assign({appId: req.params.appId}, req.query);
  gplay.reviews(opts)
    .then(toList)
    .then(paginate)
    .then(res.json.bind(res))
    .catch(next);
});