SURYAKANTSHARMA

class OnDiskCache {
 struct Item {
  let path: String
  let age: TimeInterval
  let size: Int
 }
 
 var currentItems: Set<Item> { /* .returning current items.. */ }
 

SURYAKANTSHARMA

  protocol CleanUpPolicy {
    func itemsToRemove(from items: Set<OnDiskCache.Item>) -> Set<OnDiskCache.Item>
  }

  struct MaxSizeCachePolicy: CleanUpPolicy {
    let maxSize: Int
    
    func itemsToRemove(from items: Set<OnDiskCache.Item>) -> Set<OnDiskCache.Item> {
      var itemToRemove = Set<OnDiskCache.Item>()
      let sortedItems = items.sorted { $0.age < $1.age }

SURYAKANTSHARMA

  protocol CleanUpPolicy {
    func itemsToRemove(from items: Set<OnDiskCache.Item>) -> Set<OnDiskCache.Item>
  }

  struct MaxSizeCachePolicy: CleanUpPolicy {
    let maxSize: Int
    
    func itemsToRemove(from items: Set<OnDiskCache.Item>) -> Set<OnDiskCache.Item> {
      var itemToRemove = Set<OnDiskCache.Item>()
      let sortedItems = items.sorted { $0.age < $1.age }

SURYAKANTSHARMA

struct User {
    let balance: Double
}

func saveUserBalance(user: User, buyingAmount: Double) {
   let remainingBalance  = user.balance - buyingAmount  
   // save user balance for persistance 
   UserDefaults.standard.set(remainingBalance, forKey: "userBalance")
}

SURYAKANTSHARMA

func saveUserBalance(user: User, buyingAmount: Double, defaults: UserDefaults = UserDefaults.standard) {
    let remainingBalance  = user.balance - buyingAmount
    // save user balance for persistance
    defaults.set(remainingBalance, forKey: "userBalance")
}

SURYAKANTSHARMA

class MockUserDefault: UserDefaults {
    var balance = Double()
    override func set(_ value: Double, forKey defaultName: String) {
        balance = value
    }
}

func testUserBalanceCalculation() {
    let user = User(balance: 100)
    let mockUserDefaults = MockUserDefault()

SURYAKANTSHARMA

class ProfileViewController: UIViewController {
  var user: User
  convenience init(user: User) {
    self.init(nibName:nil, bundle:nil)
    self.user = user
  }
}

SURYAKANTSHARMA

let vc = ProfileViewController()
vc.user = user 
navigationViewController.push(vc, animated: true)

SURYAKANTSHARMA

class DateFormatter {
  static func convertToUTC(localDate: Date) -> Date {
    // conversion logic
    return utcDate
  }
}

SURYAKANTSHARMA

typealias Amount = Float
struct User {
    let name: String
    let salary: Amount
}

enum PerformanceRating {
    enum Result {
        case warning(letter: String)
        case bonus(amount: Amount)