improve bridge framework code

Author: Lision

WKWebViewJavascriptBridge/WKWebViewJavascriptBridge.swift

@@ -14,14 +14,14 @@ public class WKWebViewJavascriptBridge: NSObject {
     private let iOS_Native_InjectJavascript = "iOS_Native_InjectJavascript"
     private let iOS_Native_FlushMessageQueue = "iOS_Native_FlushMessageQueue"
 
-    private weak var webView: WKWebView!
+    private weak var webView: WKWebView?
     private var base: WKWebViewJavascriptBridgeBase!
 
     public init(webView: WKWebView) {
         super.init()
         self.webView = webView
-        self.webView.configuration.userContentController.add(self, name: iOS_Native_InjectJavascript)
-        self.webView.configuration.userContentController.add(self, name: iOS_Native_FlushMessageQueue)
+        self.webView?.configuration.userContentController.add(self, name: iOS_Native_InjectJavascript)
+        self.webView?.configuration.userContentController.add(self, name: iOS_Native_FlushMessageQueue)
         base = WKWebViewJavascriptBridgeBase()
         base.delegate = self
     }
@@ -43,7 +43,7 @@ public class WKWebViewJavascriptBridge: NSObject {
     }
 
     func flushMessageQueue() {
-        webView.evaluateJavaScript("WKWebViewJavascriptBridge._fetchQueue();") { (result, error) in
+        webView?.evaluateJavaScript("WKWebViewJavascriptBridge._fetchQueue();") { (result, error) in
             if error != nil {
                 print("WKWebViewJavascriptBridge: WARNING: Error when trying to fetch data from WKWebView: \(String(describing: error))")
             }
@@ -56,7 +56,7 @@ public class WKWebViewJavascriptBridge: NSObject {
 
 extension WKWebViewJavascriptBridge: WKWebViewJavascriptBridgeBaseDelegate {
     func evaluateJavascript(javascript: String) {
-        webView.evaluateJavaScript(javascript, completionHandler: nil)
+        webView?.evaluateJavaScript(javascript, completionHandler: nil)
     }
 }
 

WKWebViewJavascriptBridge/WKWebViewJavascriptBridgeBase.swift

@@ -59,16 +59,14 @@ public class WKWebViewJavascriptBridgeBase: NSObject {
             log(message)
 
             if let responseID = message["responseID"] as? String {
-                let callback = responseCallbacks[responseID]
-                callback!(message["responseData"]!)
+                guard let callback = responseCallbacks[responseID] else { continue }
+                callback(message["responseData"])
                 responseCallbacks.removeValue(forKey: responseID)
             } else {
                 var callback: Callback?
                 if let callbackID = message["callbackID"] {
                     callback = { (_ responseData: Any?) -> Void in
-                        guard responseData != nil else { return }
-                        
-                        let msg = ["responseID": callbackID, "responseData": responseData!] as Message
+                        let msg = ["responseID": callbackID, "responseData": responseData ?? NSNull()] as Message
                         self.queue(message: msg)
                     }
                 } else {
@@ -128,7 +126,7 @@ public class WKWebViewJavascriptBridgeBase: NSObject {
         var result: String?
         do {
             let data = try JSONSerialization.data(withJSONObject: message, options: pretty ? .prettyPrinted : JSONSerialization.WritingOptions(rawValue: 0))
-            result = String(data: data, encoding: .utf8)!
+            result = String(data: data, encoding: .utf8)
         } catch let error {
             log(error)
         }