pavankataria

const promiseMachine = Machine({
  id: 'promise',
  initial: 'pending',
  states: {
    pending: {
      on: {
        // state transition (shorthand)
        // this is equivalent to { target: 'resolved' }
        RESOLVE: 'resolved',

pavankataria

const lightMachine = Machine({
  key: 'light',
  initial: 'green',
  states: {
    green: {
      on: { NEXT: "yellow" }
    },
    yellow: {      on: { NEXT: "red" }},
    red: {
      initial: 'green',

pavankataria

const allData = new Array(25).fill(0).map((_valu, i) => i + 1);
const perPage = 10;

const dataMachine = new Machine({
  id: 'dataMachine',
  initial: 'loading',
  context: {
    data: []
  },
  states: {

pavankataria

// A very cool visualisation machine
// Allows you to see what the state machine does
// And how it transitions from one state to the next
const toggleMachine = new Machine({
  id: 'toggleMachine', 
  initial: 'inactive',
  states: {
    inactive: {
      // Tell it which events the state should listen for. 
      // And you do that by defining an on property. 

pavankataria

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        
        /// 1. Capture the scene
        guard let windowScene = (scene as? UIWindowScene) else { return }
        
        /// 2. Create a new UIWindow using the windowScene constructor which takes in a window scene.
        let window = UIWindow(windowScene: windowScene)
        
        /// 3. Create a view hierarchy programmatically
        let viewController = ArticleListViewController()

pavankataria

let balanceToConvert: String? 
...
if let inputEntry = balance, inputEntry.sign == .negative {
    balanceToConvert = Int(inputEntry.input) // Can return nil
        .flatMap(Int.init)     // Convert to Int if not nil
        .flatMap { $0 * -1 }   // flip sign if not nil
        .flatMap(String.init)  // convert back to String if not nil
}
...

pavankataria

// In the flatmap method it would look something like this
switch self {
case .some(let unwrapped): 
    return transform(unwrappedValue)
case .none: 
    return nil
}

pavankataria

func processInput(_ stringNumber: String?) -> Int? {
    return stringNumber.flatMap { Int($0) }
}

pavankataria

func processInput(_ stringNumber: String?) -> Int? {
    guard let unwrappedStringNumber = stringNumber { 
        return nil
    }
    return Int(unwrappedStringNumber)
}

pavankataria

fileprivate extension UIControlState {
    static let unspecified = UIControlState(rawValue: 1 << 16)
    static let ascending = UIControlState(rawValue: 1 << 17)
    static let descending = UIControlState(rawValue: 1 << 18)
}

class SortButton: UIButton {
    private var customState: UIControlState = .unspecified {
        didSet {
            setNeedsLayout()