UIButton extension that allows replacing button with a loading indicator and back with one line of code

UIButton+spinner.swift

import UIKit

extension UIButton {
    func hideButtonAndShowSpinner() {
        self.isHidden = true

        let spinnerTag = Int(bitPattern: Unmanaged.passUnretained(self).toOpaque())
        if self.superview?.subviews.first(where: { (view) -> Bool in
            return view.isKind(of: UIActivityIndicatorView.self) && view.tag == spinnerTag
        }) != nil {
            return
        }
        
        let spinner = UIActivityIndicatorView(style: .medium)
        spinner.tag = spinnerTag
        spinner.startAnimating()
        spinner.center = self.center
        self.superview?.addSubview(spinner)
        spinner.snp.makeConstraints { (make) in
            make.center.equalTo(self)
        }
    }

    func hideSpinnerAndShowButton() {
        let spinnerTag = Int(bitPattern: Unmanaged.passUnretained(self).toOpaque())
        let spinner = self.superview?.subviews.first(where: { (view) -> Bool in
            return view.isKind(of: UIActivityIndicatorView.self) && view.tag == spinnerTag
        })

        spinner?.removeFromSuperview()
        self.isHidden = false
    }
}