Swift 3 Extension for opening target="_blank" and mailto:/tel: links in native iOS apps

WKWebViewExtension.swift

import UIKit
import WebKit

class ViewController: UIViewController {

  var webView: WKWebView = WKWebView() {
    didSet {
      webView.navigationDelegate = self
      webView.uiDelegate = self
    }
  }

  // MARK: - Override functions
  override func loadView() {
    super.loadView()
    self.webView.navigationDelegate = self
    self.webView.uiDelegate = self
  }

}
  
extension ViewController: WKNavigationDelegate, WKUIDelegate {

  func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    if webView != self.webView {
      decisionHandler(.allow)
      return
    }
    let app = UIApplication.shared
    if let url = navigationAction.request.url {
      // handle target="_blank"
      if navigationAction.targetFrame == nil {
        if app.canOpenURL(url) {
          app.openURL(url)
          decisionHandler(.cancel)
          return
        }
      }
      // handle phone and email links
      if url.scheme == "tel" || url.scheme == "mailto" {
        if app.canOpenURL(url) {
          app.openURL(url)
          decisionHandler(.cancel)
          return
        }
      }
      decisionHandler(.allow)
    }
  }

}