WKWebView+Whatsapp.swift

import WebKit

class ViewController: UIViewController, WKNavigationDelegate {
    
    @IBOutlet weak var webView: WKWebView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        webView.uiDelegate = self
        webView.navigationDelegate = self
        webView.allowsBackForwardNavigationGestures = true

        let myURL = URL(string: [====URL====])
        let myRequest = URLRequest(url: myURL!)
        webView.load(myRequest)
    }
    
    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
        
        guard let redirectURL = (navigationAction.request.url) else {
            decisionHandler(.cancel)
            return
        }
        
        if (redirectURL.absoluteString.contains("tel:") ) {
            UIApplication.shared.open(redirectURL, options: [:], completionHandler: nil)
        }
        
        if (redirectURL.absoluteString.contains("whatsapp") ) {
            UIApplication.shared.open(redirectURL, options: [:], completionHandler: nil)
        }
        
        decisionHandler(.allow)
    }
}

extension ViewController: WKUIDelegate {

    func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {
        
        guard let url = navigationAction.request.url else {
            return nil
        }
        
        guard let targetFrame = navigationAction.targetFrame, targetFrame.isMainFrame else {
            webView.load(URLRequest(url: url))
            return nil
        }
        return nil
    }
}