KanshuYokoo

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Assume there are firstView and SecondView in the Main.storyboard 
        // open SecondView
        window = UIWindow(frame: UIScreen.main.bounds)
        let storyboad: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let newViewController = storyboad.instantiateViewController(withIdentifier: "SecondView") as UIViewController
        window!.rootViewController = newViewController
        window!.makeKeyAndVisible()
        return true
    }

KanshuYokoo

let emailRegX = "[A-Z0-9a-z?./_%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}"
let emailTest = NSPredicate.init(format: "SELF MATCHES %@", emailRegX)
let isEmail = emailTest.evaluate(with: "[email protected]")

KanshuYokoo

import UIKit

@IBDesignable class ButtonRadius: UIButton {

    @IBInspectable var cornerRadius: CGFloat = 0.0 {
        didSet{
            self.layer.cornerRadius = cornerRadius
        }
    }
    

KanshuYokoo

import UIKit

@IBDesignable class CustomBorderView: UIView {

    @IBInspectable var cornerRadius: CGFloat = 0{
        didSet{
            self.layer.cornerRadius = cornerRadius
        }
    }
    

KanshuYokoo

const { width, height } = Dimensions.get('window')
const sizeStyle = {
      width: width,
      height: height 
    }
    
const styleImage = {
      flex: 1,
      justifyContent: 'center',
      alignItems: 'center'

KanshuYokoo

import { Dimensions, Platform } from 'react-native';

export function isIphoneX() {
  const dimWindow = Dimensions.get('window')
  return (
    Platform.OS === 'ios' &&
      (isIPhoneXSize(dimWindow) || isIPhoneXRMAXSize(dimWindow))
  )
}
export function isIPhoneXSize(window) {

KanshuYokoo

  Style: PropTypes.oneOfType(
    [
      PropTypes.number,
      PropTypes.object,
      PropTypes.array
    ]
  )

KanshuYokoo

IBOutlet weak var field1: UITextField!

if(field1.text?.isEmpty ?? true) {
// field is empty
  return true
} else {
// field is NOT empty
  return false
}

KanshuYokoo

DispatchQueue.main.async(execute: {
  // call any function ex. doSomething()
   self.doSomething() 
 })

KanshuYokoo

        UIControl().sendAction(#selector(NSXPCConnection.suspend),
                               to: UIApplication.shared, for: nil)