swift3からswift4への移行問題

Type 'AVCaptureDevice' has no member 'defaultDevice'
let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
let captureDevice = AVCaptureDevice.default(for: .video)
https://stackoverflow.com/questions/46945104/type-avcapturedevice-has-no-member-defaultdevice

UIImagePickerControllerOriginalImage
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
let image = info[.originalImage] as! UIImage
https://teratail.com/questions/155873

UIImageJPEGRepresentation has been replaced by instance method UIImage.jpegData(compressionQuality:)
https://stackoverflow.com/questions/51531165/uiimagejpegrepresentation-has-been-replaced-by-instance-method-uiimage-jpegdata
let imageData = UIImageJPEGRepresentation(image, 0.75)
let imageData = image.jpegData(compressionQuality: 0.75)

バーコードを読み込ませるiPhoneアプリ作成に関して
let device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
let device = AVCaptureDevice.default(for: .video)
https://teratail.com/questions/100583