while text is nil or empty display activity indicator on uilabel

LabelWithActivityIndicator.swift

import UIKit

class LabelWithActivityIndicator: UILabel {
    private var activityIndicator: UIActivityIndicatorView = {
        let indicator = UIActivityIndicatorView(style: .gray)
        indicator.startAnimating()
        indicator.hidesWhenStopped = true
        return indicator
    }()
    
    override var text: String? {
        didSet {
            guard let text = text,
                !text.isEmpty else {
                    showLoading()
                    return
            }
            hideLoading()
        }
    }
}

private extension LabelWithActivityIndicator {
    private func showLoading() {
        activityIndicator.translatesAutoresizingMaskIntoConstraints = false
        addSubview(activityIndicator)
        activityIndicator.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
        activityIndicator.topAnchor.constraint(equalTo: topAnchor).isActive = true
        activityIndicator.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
        activityIndicator.startAnimating()
    }
    
    private func hideLoading() {
        activityIndicator.stopAnimating()
        activityIndicator.removeFromSuperview()
    }
}