Avoiding repeating code in swift

Question

In following code, based on the string comparison I am deciding on which VC will be shown.

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    dataObj = frc.object(at: indexPath) as! Data_Object
    var pvc: UIViewController?

    if dataObj.type == "X" {

        let obj = MainStoryboard().instantiateViewController(withIdentifier: "XVC") as! XVC
        obj.data = dataObj
        obj.isFull = true
        obj.delegate = self
        pvc = obj as UIViewController

    } else if dataObj.type == "Y" {

        let obj = MainStoryboard().instantiateViewController(withIdentifier: "YVC") as! YVC
        obj.data = dataObj
        obj.isFull = true
        obj.delegate = self
        pvc = obj as UIViewController

    } else {

        let obj = MainStoryboard().instantiateViewController(withIdentifier: "ZVC") as! ZVC
        obj.data = dataObj
        obj.isFull = true
        obj.delegate = self
        pvc = obj as UIViewController
    }

    obj.modalPresentationStyle = .popover
    let popPVC = pvc?.popoverPresentationController
    popPVC?.sourceView = self.view
    self.present(pvc!, animated: true, completion: nil)
}

Now, all of the code is repetitive except class name and I want to avoid that. But, swift do not have NSClassFromString

How do I accomplish this? Should I use Generics/Templates? Any suggestions!

Sorry in advance, if I am missing something silly here.

Answer 1

The removal of duplication is obvious:

let identifier: String

switch dataObj.type {
    case "X":
       identifier = "XVC"
    case "Y":
       identifier = "YVC"
    default:
       identifier = "ZVC"
}

let pvc = MainStoryboard().instantiateViewController(withIdentifier: identifier) as! PVC
pvc.data = dataObj
pvc.isFull = true
pvc.delegate = self

Where PVC is the common superclass of your 3 controllers, e.g. :

class PVC : UIViewController {}
class XVC : PVC {}
class YVC : PVC {}
class ZVC : PVC {}

If your 3 classes don't have a common superclass, you can use a protocol instead:

protocol PVC : class {
   var data: ...
   var isFul: ...
   weak var delegate: ...
}

and implement it by your 3 classes:

In short, to remove the duplication, you need to add a common interface to the 3 controllers. Either using a common superclass or protocol.