Swift 3 – some snippets..

• if let paypal = user.paypal {
  // paypal != nil
  } else {
  // paypal == nil
  }
• guard let paypal = user.paypal else {
  // paypal == nil
  return
  }
• Handler :
  • VC 1: (CashoutContentVC)

    var loadTotalBalanceHandler: (()->())?  

    if (condition) {

                         if let callback = self.loadTotalBalanceHandler {

                            callback()

                       }
    }

  • VC 2:

    let cashoutVC = storyboard.instantiateViewController(withIdentifier: “CASH OUT”) as! CashoutContentVC

            cashoutVC.loadTotalBalanceHandler = {[weak self] in

                self?.loadTotalBalance() //things need to do when callback

            }

    //example 2 :  pass a Double from vc1 -> vc2 

  • VC1:
    var ratingScoreHandler: ((_ score: Double) -> ())?

    if (condition) {
    

                   if let callback = self.ratingScoreHandler {

                        callback(rating)

                    }
    }

  • VC 2:

    let ratingVC = RatingVC(nibName: “RatingVC”, bundle: nil)

    ratingVC.ratingScoreHandler = { [weak self] (score) in

                if let strongSelf = self {

                    strongSelf.ratingScore = Int(score) //things need to do when callback

                }

            }