open external links in iOS WKWebview like mailto:, whatsapp, tell etc..

ViewController.swift

    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        if navigationAction.request.url?.scheme == "tel" || navigationAction.request.url?.scheme == "mailto" {
            UIApplication.shared.open(navigationAction.request.url!)
            decisionHandler(.cancel)
        } else {
            decisionHandler(.allow)
        }
        
    }