I try to show data from API Response. I have json and DataService.
When ViewController is load, my presenter give away data from my Service.
I don’t know why, but I make two request to my service. First time I get only one empty cell and the second time I get other data.

Image from view hierarchy:

My DataService:

class DataService {
    
    func getRouts(completion: @escaping (APIResponse) -> Void?) {
        
        let urlString = "https://travel.wildberries.ru/statistics/v1/cheap"
        
        guard let url = URL(string: urlString) else { return }
        
        let task = URLSession.shared.dataTask(with: url) { data, response, error in
            guard let data = data, error == nil else { return }
            
            do {
                let jsonResults = try JSONDecoder().decode(APIResponse.self, from: data)
                completion(jsonResults)
            }
            catch {
                print{error}
            }
        }
        task.resume()
    }
}

My presenter

protocol PresenterProtocol: AnyObject {
    
    func viewDidLoad()
}

final class ListTicketsModulPresenter: PresenterProtocol {

    let dataService = DataService()
    
    weak var listTicketsViewController: ListTicketsViewController?
    
    func viewDidLoad() {
        dataService.getRouts { [weak self] results in
            DispatchQueue.main.async {
                print(results)
                self?.listTicketsViewController?.configure(with: results)
            }
        }
    }
}

My ViewController:

final class ListTicketsViewController: UIViewController, ListTicketsViewControllerProtocol {

    var presenter: PresenterProtocol
    
    let tableView: UITableView = {
        let tableView = UITableView()
        tableView.backgroundColor = UIColor.white
        tableView.separatorColor = .white
        tableView.allowsSelection = false
        tableView.translatesAutoresizingMaskIntoConstraints = false
        return tableView
    }()
    
    var numberOfRows: Int?
    var startCityNameArray: [String]?
    var endCityNameArray: [String]?
    var startDateArray: [String]?
    var endDateArray: [String]?
    var price: [Int]?

...

override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .white

        view.addSubview(tableView)
        
        setupTableView()
        
        presenter.viewDidLoad()
        
    }

    //Functions
    
    func configure(with model: APIResponse) {
        self.startCityNameArray = model.data.map { $0.startCity }
        self.endCityNameArray = model.data.map { $0.endCity }
        self.numberOfRows = model.data.count
        self.startDateArray = model.data.map { $0.startDate }
        self.endDateArray = model.data.map { $0.endDate }
        self.price = model.data.map { $0.price }
        self.tableView.reloadData()
    }

...

}