SwDin: Simple constructor Injection example.

ConstructorInjection.swift

import UIKit

class FirstViewController: UIViewController {
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    // When we want to goto the SecondViewController.
    let repository = SomeRepository()
    let service = SomeService()
    let viewModel = ViewModel(repository: repository, service: service)
    let secondViewController = SecondViewController(viewModel: viewModel)
    self.present(viewController, animated:true, completion:nil)
   }
}