cjnevin

let redView = UIView()
redView.backgroundColor = .red
addSubview(redView) {
   $0.edges(20).equalToSuperview()
}

cjnevin

let redView = UIView()
redView.backgroundColor = .red
addSubview(redView)
redView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
  redView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 20),
  redView.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -20),
  redView.topAnchor.constraint(equalTo: topAnchor, constant: 20),
  redView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -20)
])

cjnevin

final class LoginViewController: UIViewController {
  @EmailStyle private var emailTextField
  @PasswordStyle private var passwordTextField
  @SubmitStyle private var submitButton
}

cjnevin

class FormTextField: UITextField {
  var isValid: Bool = false {
    didSet { layer.borderColor = isValid ? validColor.cgColor : invalidColor.cgColor }
  }
  var validColor: UIColor = .black
  var invalidColor: UIColor = .black
}

@propertyWrapper
struct EmailStyle {

cjnevin

@propertyWrapper
struct EmailStyle {
  var wrappedValue: UITextField
  init(_ textField: UITextField = .init()) {
    wrappedValue = textField
    textField.autocapitalizationType = .none
    textField.autocorrectionType = .no
    textField.placeholder = "Email"
    textField.keyboardType = .emailAddress
  }

cjnevin

final class LoginViewController: UIViewController {
  private lazy var emailTextField = UITextField()
  private lazy var passwordTextField = UITextField()
  private lazy var submitButton = UIButton()

  override func viewDidLoad() {
    super.viewDidLoad()
    emailTextField.keyboardType = .emailAddress
    emailTextField.autocapitalizationType = .none
    emailTextField.autocorrectionType = .no

cjnevin

import UIKit

@resultBuilder
enum AutoLayoutBuilder {
    /// Required by every result builder to build combined results from statement blocks.
    static func buildBlock(_ components: ConstraintProvider...) -> [NSLayoutConstraint] {
        components.flatMap(\.constraints)
    }

    /// Provides support for `for..in` loops.

cjnevin

extension Sequence where Element: Hashable {
    func removingDuplicates() -> [Element] {
        var uniques = Set<Element>()
        return filter { uniques.insert($0).inserted }
    }

    mutating func removeDuplicates() {
        self = removingDuplicates()
    }
}

cjnevin

import UIKit

// Domain layer should be platform agnostic rules that
// can be fully tested against stubs and spies. This gives
// us confidence our business logic is working even when
// we may have issues with particular platforms integration
// layers.
//
// Integration layer could be split out per platform. 
// For example on macOS you could check a MySQL database

cjnevin

import Combine

public extension Publishers {
    /// Map each case in an enum to a corresponding `Publisher`.
    /// All `Publishers` must adhere to same response type.
    /// Order of `Publishers` must match `CaseIterable` order.
    struct CaseMap<A: Publisher, B: Publisher>: Publisher where A.Output: CaseIterable, A.Output: Equatable, A.Failure == B.Failure {
        public typealias Output = B.Output
        public typealias Failure = B.Failure