Example of implementation of Domain Events in Swift. The snippet illustrates Domain Events in a Service with RxSwift

DomainEvents-3.swift

import RxSwift
import UIKit

class ListingListViewController: UIViewController {
    let contentView: ListingListView
    let service: ListingService
    let disposeBag: DisposeBag
      
    init(service: ListingService) {
        self.contentView = ListingListView()
        self.service = service
        super.init(nibName: nil, bundle: nil)
    }
  
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.white
        contentView.frame = view.frame
        view.addSubview(contentView)
        
        // ...
        
        let params = ListingServiceSearchParams()
        service.search(params: params) { [weak self] result in
            guard let listings = result.data else { return }
            self?.contentView.listings = listings
        }
        
        service.events.subscribe(onNext: { [weak self] event in
            guard let `self` = self else { return }
            switch event {
            case let .create(listing):
                self.contentView.create(listing: listing)
            case let .update(listing):
                self.contentView.update(listing: listing)
            case let .delete(listing):
                self.contentView.delete(listing: listing)
            }
        }, onError: { error in
        }, onCompleted: {
        }, onDisposed: {
        }).disposed(by: disposeBag)
        
        // ...
    }
}

class ListingListView: UIView, UITableViewDataSource, UITableViewDelegate {
    private let tableView = UITableView()
    var listings: [Listing] = [] {
        didSet {
            tableView.reloadData()
        }
    }
      
    // ...
    
    func create(listing: Listing) {
        tableView.beginUpdates()
        defer { tableView.endUpdates() }
        
        listings.append(listing)
        guard let indexPath = indexPathFor(listing: listing) else { return }
        tableView.insertRows(at: [indexPath], with: .automatic)
    }
    
    func update(listing: Listing) {
        guard let indexPath = indexPathFor(listing: listing) else { return }
        listings[indexPath.row] = listing
        tableView.reloadRows(at: [indexPath], with: .automatic)
    }
    
    func delete(listing: Listing) {
        tableView.beginUpdates()
        defer { tableView.endUpdates() }
        
        guard let indexPath = indexPathFor(listing: listing) else { return }
        listings.remove(at: indexPath.row)
        tableView.deleteRows(at: [indexPath], with: .automatic)
    }
    
    // ...
}