MVVM View

DateView.swift

import UIKit
import Foundation

class DateView: UIViewController {

    var viewModel: DateViewModel?

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }

    // MARK: Init
    private func setup() {
        let view = self
        let viewModel = DateViewModel()
        view.viewModel = viewModel
    }

    // MARK: View lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()
        registerInViewModel()
        setupView()
    }

    // MARK: ViewModel setup
    private func registerInViewModel() {
        viewModel?.updateDate = updateDateClosure
        viewModel?.fetchDate()
    }

    @IBOutlet private weak var dateTextfield: UILabel!
    lazy var updateDateClosure: (Date) -> Void = { [weak self] (date) in
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "en_US")
        self?.dateTextfield.text = dateFormatter.string(from: date)
    }

    // MARK: View setup
    private func setupView() {
        self?.dateTextfield.text = "Updating..."
    }
}