piyushdec

class HomeViewController: UIViewController {
    private let user: User
    private let apiService: ApiService
    private lazy var name = UILabel()

    init(user: User, apiService: ApiService) {
        self.user = user
        self.apiService = apiService
        super.init(nibName: nil, bundle: nil)
    }

piyushdec

typealias CompletionBlock = (Data?) -> Void

protocol NetworkService {
    func make(request: URLRequest, completionHandler: @escaping CompletionBlock)
}

extension URLSession: NetworkService {
      func make(request: URLRequest, completionHandler: @escaping CompletionBlock) {
        let task = self.dataTask(with: request) { data, _, _ in
            completionHandler(data)

piyushdec

struct User {
 let name: String   
}

class UserController {
    static let shared = UserController()
    var currentUser: User?
    
    private init() { 
        //don't forget to make this private

piyushdec

import UIKit

typealias UserDataSource = UITableViewDiffableDataSource<UsersViewController.Section, User>
typealias UserSnapshot = NSDiffableDataSourceSnapshot<UsersViewController.Section, User>

class UsersViewController: UITableViewController {
    var users = [User]()
    var datasource: UserDataSource!
    
    func configureDataSource() {

piyushdec

collectionView?.performBatchUpdates({
    self.collectionView?.deleteItemsAtIndexPaths([NSIndexPath(forRow: 0, inSection: 0), NSIndexPath(forRow: 3, inSection: 0)])
    self.collectionView?.reloadItemsAtIndexPaths([NSIndexPath(forRow: 1, inSection: 0), NSIndexPath(forRow: 6, inSection: 0)])
    self.collectionView?.insertItemsAtIndexPaths([NSIndexPath(forRow: 5, inSection: 0), NSIndexPath(forRow: 7, inSection: 0)])
    self.collectionView?.insertItemsAtIndexPaths([NSIndexPath(forRow: 2, inSection: 0), NSIndexPath(forRow: 4, inSection: 0)])
}, completion: nil)

piyushdec

let downloadOperation = MyDownloadOperation()
let filterOperation = MyFilterOperation()
filterOperation.addDependency(downloadOperation)

piyushdec

class MainViewController: UIViewController {
    var imageRecords: [ImageRecord] = []
    let pendingOperations = PendingOperations()
}

extension MainViewController: UITableViewDataSource {
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "identifier", for: indexPath)

piyushdec

func fetchImageDataSource() {
  let request = URLRequest(url: "https://your-server-url-to-fetch-endpoints")
  let task = URLSession(configuration: .default).dataTask(with: request) { data, response, error in
       self.imagesRecord.append(record0...<recordn)
       DispatchQueue.main.async {
         self.tableView.reloadData()
       }
    }
  task.resume()
}

piyushdec

class CustomOperation: Operation {
    
    // MARK: - Types
    
    //Step 1: define oppration states
    
    enum State {
        case isReady, isExecuting, isFinished
        

piyushdec

class ImageDownloadHelper: SwiftOperation {
  //1
  let imageRecord: ImageRecord
  
  //2
  init(_ imageRecord: ImageRecord) {
    self.imageRecord = imageRecord
  }
  
  //3