Tap publisher execute twice in Combine

Question

I'd like not to use saveButton.addTarget(:selector:event) that's why I try to use tap publisher from CombineCocoa framework like this

 saveButton.tapPublisher.sink {  _ in
        print("tap") // tap twice
    }
    .store(in: &subscriptions)

and when I tap saveButton then 'tap' printed twice.

Also I try to use from Combine framework

saveButton.publisher(for: .touchUpInside) 

but have the same result.

My code here

class ArticleVC: UIViewController {
    let saveButton: UIButton = {
        let btn = UIButton()
        btn.setTitle("Save", for: .normal)
        return btn
    }()
    
    var subscriptions: Set<AnyCancellable> = []
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // add to view
        view.addSubview(saveButton)
        didTapSave()
        saveButton.snp.makeConstraints {
            $0.centerX.centerY.equalToSuperview()
        }
        
        didTapSave()
    }
    
    func didTapSave() {
//        saveButton.tapPublisher.sink(receiveValue: { _ in
//            print("tap")  // twice printed 'tap'
//        })
//        .store(in: &subscriptions)
        /// OR
        saveButton.publisher(for: .touchUpInside).sink { _ in
            print("tap") // twice printed 'tap'
        }
        .store(in: &subscriptions)
    }
}

What the reason for it?

Answer 1

My guess is that you are creating the pipeline twice. But you have not shown where you create the pipeline, so that is just a guess. [EDIT: Well after I posted this answer, you posted your code in the question, and my guess turned out to be obviously correct, as we can now see you creating the pipeline twice.]

To support this, I'll show what I did:

• I created a new iOS project.

• I put a button in the interface and hooked an outlet from my ViewController.

• I installed the package https://github.com/CombineCommunity/CombineCocoa.git

• I configured my ViewController code:

import UIKit
import Combine
import CombineCocoa

class ViewController: UIViewController {
    @IBOutlet weak var button: UIButton!
    var storage = Set<AnyCancellable>()
    override func viewDidLoad() {
        super.viewDidLoad()
        button.tapPublisher
            .sink { _ in print("tap") }
            .store(in: &storage)
    }
}

That is all the code there is. I run the project, I tap the button, I see "tap" once. The end.