const usersObj = {};
const kvusersObj = {};

input.forEach(place => {
  place.reviews.forEach(review => {
    if (review.language === 'cs' &&
         review.userProfile.contributionCounts.sumReview >= 2) {
      const userdata = {
        username: review.userProfile.username,
        url: `https://www.tripadvisor.ru/${review.userProfile.route.url}`,
        citypage: `https://www.tripadvisor.ru/members-citypage/${review.userProfile.username}/g274697`,
        reviews: review.userProfile.contributionCounts.sumReview,
        location: review.userProfile.hometown &&
          review.userProfile.hometown.location &&
          review.userProfile.hometown.location.name || '',
      };
      usersObj[userdata.username] = userdata;
      if (review.userProfile.hometown &&
          review.userProfile.hometown.location &&
          review.userProfile.hometown.location.additionalNames.long === 'Karlovy Vary, Czech Republic') {
        kvusersObj[userdata.username] = userdata;
      }
    }
  });
});

const users = Object.keys(usersObj).map(key => usersObj[key]);
const kvusers = Object.keys(kvusersObj).map(key => kvusersObj[key]);

const csvAllUsers = users.map(user => {
  return [user.username, user.location, user.reviews, user.url, user.citypage].join(',');
});
const csvKVUsers = kvusers.map(user => {
  return [user.username, user.location, user.reviews, user.url, user.citypage].join(',');
});

const result = [
  'ALL USERS,,,,',
  'login,location,reviews,url,citypage',
  ...csvAllUsers,
  ',,,,',
  ',,,,',
  'KARLOVY VARY USERS,,,,',
  ...csvKVUsers,
];
result;