Merge upstream

.all-contributorsrc

         "code",
         "doc"
       ]
+    },
+    {
+      "login": "jordansexton",
+      "name": "Jordan Sexton",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1173161?v=4",
+      "profile": "https://stylisted.com",
+      "contributions": [
+        "code",
+        "doc"
+      ]
+    },
+    {
+      "login": "MalcolmScruggs",
+      "name": "Malcolm Scruggs",
+      "avatar_url": "https://avatars1.githubusercontent.com/u/22333355?v=4",
+      "profile": "https://github.com/MalcolmScruggs",
+      "contributions": [
+        "code",
+        "tool",
+        "test"
+      ]
     }
   ],
   "contributorsPerLine": 7

README.md

 # React Native WebView - a Modern, Cross-Platform WebView for React Native
-[![star this repo](http://githubbadges.com/star.svg?user=react-native-community&repo=react-native-webview&style=flat)](https://github.com/react-native-community/react-native-webview) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![All Contributors](https://img.shields.io/badge/all_contributors-6-orange.svg?style=flat-square)](#contributors) [![Known Vulnerabilities](https://snyk.io/test/github/react-native-community/react-native-webview/badge.svg?style=flat-square)](https://snyk.io/test/github/react-native-community/react-native-webview) 
+[![star this repo](http://githubbadges.com/star.svg?user=react-native-community&repo=react-native-webview&style=flat)](https://github.com/react-native-community/react-native-webview) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![All Contributors](https://img.shields.io/badge/all_contributors-8-orange.svg?style=flat-square)](#contributors) [![Known Vulnerabilities](https://snyk.io/test/github/react-native-community/react-native-webview/badge.svg?style=flat-square)](https://snyk.io/test/github/react-native-community/react-native-webview) 
 
 **React Native WebView** is a modern, well-supported, and cross-platform WebView for React Native. It is intended to be a replacement for the built-in WebView (which will be [removed from core](https://github.com/react-native-community/discussions-and-proposals/pull/3)).
 
 
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
 <!-- prettier-ignore -->
-| [<img src="https://avatars1.githubusercontent.com/u/6181446?v=4" width="100px;" alt="Thibault Malbranche"/><br /><sub><b>Thibault Malbranche</b></sub>](https://twitter.com/titozzz)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Code") [🤔](#ideas-titozzz "Ideas, Planning, & Feedback") [👀](#review-titozzz "Reviewed Pull Requests") [📖](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Documentation") [🚧](#maintenance-titozzz "Maintenance") [⚠️](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Tests") [🚇](#infra-titozzz "Infrastructure (Hosting, Build-Tools, etc)") [💬](#question-titozzz "Answering Questions") | [<img src="https://avatars3.githubusercontent.com/u/1479215?v=4" width="100px;" alt="Jamon Holmgren"/><br /><sub><b>Jamon Holmgren</b></sub>](https://jamonholmgren.com)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Code") [🤔](#ideas-jamonholmgren "Ideas, Planning, & Feedback") [👀](#review-jamonholmgren "Reviewed Pull Requests") [📖](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Documentation") [🚧](#maintenance-jamonholmgren "Maintenance") [⚠️](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Tests") [💡](#example-jamonholmgren "Examples") [💬](#question-jamonholmgren "Answering Questions") | [<img src="https://avatars1.githubusercontent.com/u/2570562?v=4" width="100px;" alt="Andrei Pfeiffer"/><br /><sub><b>Andrei Pfeiffer</b></sub>](https://github.com/andreipfeiffer)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=andreipfeiffer "Code") [👀](#review-andreipfeiffer "Reviewed Pull Requests") [🤔](#ideas-andreipfeiffer "Ideas, Planning, & Feedback") | [<img src="https://avatars0.githubusercontent.com/u/5347038?v=4" width="100px;" alt="Michael Diarmid"/><br /><sub><b>Michael Diarmid</b></sub>](https://twitter.com/mikediarmid)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=Salakar "Code") [👀](#review-Salakar "Reviewed Pull Requests") [🤔](#ideas-Salakar "Ideas, Planning, & Feedback") [🔧](#tool-Salakar "Tools") | [<img src="https://avatars3.githubusercontent.com/u/932981?v=4" width="100px;" alt="Scott Mathson"/><br /><sub><b>Scott Mathson</b></sub>](http://smathson.github.io)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=smathson "Code") [📖](https://github.com/react-native-community/react-native-webview/commits?author=smathson "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/8221990?v=4" width="100px;" alt="Margaret"/><br /><sub><b>Margaret</b></sub>](https://github.com/YangXiaomei)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=YangXiaomei "Code") [📖](https://github.com/react-native-community/react-native-webview/commits?author=YangXiaomei "Documentation") |
-| :---: | :---: | :---: | :---: | :---: | :---: |
+| [<img src="https://avatars1.githubusercontent.com/u/6181446?v=4" width="100px;" alt="Thibault Malbranche"/><br /><sub><b>Thibault Malbranche</b></sub>](https://twitter.com/titozzz)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Code") [🤔](#ideas-titozzz "Ideas, Planning, & Feedback") [👀](#review-titozzz "Reviewed Pull Requests") [📖](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Documentation") [🚧](#maintenance-titozzz "Maintenance") [⚠️](https://github.com/react-native-community/react-native-webview/commits?author=titozzz "Tests") [🚇](#infra-titozzz "Infrastructure (Hosting, Build-Tools, etc)") [💬](#question-titozzz "Answering Questions") | [<img src="https://avatars3.githubusercontent.com/u/1479215?v=4" width="100px;" alt="Jamon Holmgren"/><br /><sub><b>Jamon Holmgren</b></sub>](https://jamonholmgren.com)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Code") [🤔](#ideas-jamonholmgren "Ideas, Planning, & Feedback") [👀](#review-jamonholmgren "Reviewed Pull Requests") [📖](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Documentation") [🚧](#maintenance-jamonholmgren "Maintenance") [⚠️](https://github.com/react-native-community/react-native-webview/commits?author=jamonholmgren "Tests") [💡](#example-jamonholmgren "Examples") [💬](#question-jamonholmgren "Answering Questions") | [<img src="https://avatars1.githubusercontent.com/u/2570562?v=4" width="100px;" alt="Andrei Pfeiffer"/><br /><sub><b>Andrei Pfeiffer</b></sub>](https://github.com/andreipfeiffer)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=andreipfeiffer "Code") [👀](#review-andreipfeiffer "Reviewed Pull Requests") [🤔](#ideas-andreipfeiffer "Ideas, Planning, & Feedback") | [<img src="https://avatars0.githubusercontent.com/u/5347038?v=4" width="100px;" alt="Michael Diarmid"/><br /><sub><b>Michael Diarmid</b></sub>](https://twitter.com/mikediarmid)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=Salakar "Code") [👀](#review-Salakar "Reviewed Pull Requests") [🤔](#ideas-Salakar "Ideas, Planning, & Feedback") [🔧](#tool-Salakar "Tools") | [<img src="https://avatars3.githubusercontent.com/u/932981?v=4" width="100px;" alt="Scott Mathson"/><br /><sub><b>Scott Mathson</b></sub>](http://smathson.github.io)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=smathson "Code") [📖](https://github.com/react-native-community/react-native-webview/commits?author=smathson "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/8221990?v=4" width="100px;" alt="Margaret"/><br /><sub><b>Margaret</b></sub>](https://github.com/YangXiaomei)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=YangXiaomei "Code") [📖](https://github.com/react-native-community/react-native-webview/commits?author=YangXiaomei "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/1173161?v=4" width="100px;" alt="Jordan Sexton"/><br /><sub><b>Jordan Sexton</b></sub>](https://stylisted.com)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=jordansexton "Code") [📖](https://github.com/react-native-community/react-native-webview/commits?author=jordansexton "Documentation") |
+| :---: | :---: | :---: | :---: | :---: | :---: | :---: |
+| [<img src="https://avatars1.githubusercontent.com/u/22333355?v=4" width="100px;" alt="Malcolm Scruggs"/><br /><sub><b>Malcolm Scruggs</b></sub>](https://github.com/MalcolmScruggs)<br />[💻](https://github.com/react-native-community/react-native-webview/commits?author=MalcolmScruggs "Code") [🔧](#tool-MalcolmScruggs "Tools") [⚠️](https://github.com/react-native-community/react-native-webview/commits?author=MalcolmScruggs "Tests") |
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
 This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!

android/build.gradle

 buildscript {
   //Buildscript is evaluated before everything else so we can't use getExtOrDefault
-  def kotlin_version = rootProject.ext.has('kotlinVersion') ? rootProject.ext.get('kotlinVersion') : project.properties['ReactNativeWebview_kotlinVersion']
+  def kotlin_version = rootProject.ext.has('kotlinVersion') ? rootProject.ext.get('kotlinVersion') : project.properties['ReactNativeWebView_kotlinVersion']
 
   repositories {
     google()
 }
 
 def getExtOrDefault(name) {
-  return rootProject.ext.has(name) ? rootProject.ext.get(name) : project.properties['ReactNativeWebview_' + name]
+  return rootProject.ext.has(name) ? rootProject.ext.get(name) : project.properties['ReactNativeWebView_' + name]
 }
 
 def getExtOrIntegerDefault(name) {
-  return rootProject.ext.has(name) ? rootProject.ext.get(name) : (project.properties['ReactNativeWebview_' + name]).toInteger()
+  return rootProject.ext.has(name) ? rootProject.ext.get(name) : (project.properties['ReactNativeWebView_' + name]).toInteger()
 }
 
 apply plugin: 'com.android.library'

android/gradle.properties

-ReactNativeWebview_kotlinVersion=1.3.11
-ReactNativeWebview_compileSdkVersion=28
-ReactNativeWebview_buildToolsVersion=28.0.3
-ReactNativeWebview_targetSdkVersion=28
-ReactNativeWebview_supportLibVersion=28.0.0
+ReactNativeWebView_kotlinVersion=1.3.11
+ReactNativeWebView_compileSdkVersion=28
+ReactNativeWebView_buildToolsVersion=28.0.3
+ReactNativeWebView_targetSdkVersion=28
+ReactNativeWebView_supportLibVersion=28.0.0

android/src/main/java/com/reactnativecommunity/webview/RNCWebViewManager.java

 
   protected static final String HTML_ENCODING = "UTF-8";
   protected static final String HTML_MIME_TYPE = "text/html";
-  protected static final String BRIDGE_NAME = "__REACT_WEB_VIEW_BRIDGE";
+  protected static final String JAVASCRIPT_INTERFACE = "ReactNativeWebView";
 
   protected static final String HTTP_METHOD_POST = "POST";
 
 
       if (!mLastLoadFailed) {
         RNCWebView reactWebView = (RNCWebView) webView;
+
         reactWebView.callInjectedJavaScript();
-        reactWebView.linkBridge();
+
         emitFinishEvent(webView, url);
       }
     }
         mContext = c;
       }
 
+      /**
+       * This method is called whenever JavaScript running within the web view calls:
+       *   - window[JAVASCRIPT_INTERFACE].postMessage
+       */
       @JavascriptInterface
       public void postMessage(String message) {
         mContext.onMessage(message);
       }
 
       messagingEnabled = enabled;
+
       if (enabled) {
-        addJavascriptInterface(createRNCWebViewBridge(this), BRIDGE_NAME);
-        linkBridge();
+        addJavascriptInterface(createRNCWebViewBridge(this), JAVASCRIPT_INTERFACE);
       } else {
-        removeJavascriptInterface(BRIDGE_NAME);
+        removeJavascriptInterface(JAVASCRIPT_INTERFACE);
       }
     }
 
       }
     }
 
-    public void linkBridge() {
-      if (messagingEnabled) {
-        if (ReactBuildConfig.DEBUG && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
-          // See isNative in lodash
-          String testPostMessageNative = "String(window.postMessage) === String(Object.hasOwnProperty).replace('hasOwnProperty', 'postMessage')";
-          evaluateJavascript(testPostMessageNative, new ValueCallback<String>() {
-            @Override
-            public void onReceiveValue(String value) {
-              if (value.equals("true")) {
-                FLog.w(ReactConstants.TAG, "Setting onMessage on a WebView overrides existing values of window.postMessage, but a previous value was defined");
-              }
-            }
-          });
-        }
-
-        evaluateJavascriptWithFallback("(" +
-          "window.originalPostMessage = window.postMessage," +
-          "window.postMessage = function(data) {" +
-            BRIDGE_NAME + ".postMessage(String(data));" +
-          "}" +
-        ")");
-      }
-    }
-
     public void onMessage(String message) {
       dispatchEvent(this, new TopMessageEvent(this.getId(), message));
     }

babel.config.js

+module.exports = function (api) {
+    api && api.cache(false);
+    return {
+      env: {
+        test: {
+          presets: [
+            "module:metro-react-native-babel-preset"
+          ],
+        }
+      }
+    };
+  }

docs/Contributing.md

 - After pulling this repo and installing all dependencies, you can run flow on iOS and Android-specific files using the commands:
   - `yarn test:ios:flow` for iOS
   - `yarn test:android:flow` for Android
+- You can run Jest tests using the command: `yarn test:js`
 - If you want to add another React Native platform to this repository, you will need to create another `.flowconfig` for it. If your platform is `example`, copy the main flowconfig and rename it to `.flowconfig.example`. Then edit the config to ignore other platforms, and add `.*/*[.]example.js` to the ignore lists of the other platforms. Then add an entry to `package.json` like this:
   - `"test:example:flow": "flow check --flowconfig-name .flowconfig.example"`
 - Currently you need to install React Native 0.57 to be able to test these types - `flow check` will not pass against 0.56.

docs/Reference.md

 
 This document lays out the current public properties and methods for the React Native WebView.
 
-> **Security Warning:** Currently, `onMessage` and `postMessage` do not allow specifying an origin. This can lead to cross-site scripting attacks if an unexpected document is loaded within a `WebView` instance. Please refer to the MDN documentation for [`Window.postMessage()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage) for more details on the security implications of this.
-
 ## Props Index
 
 - [`source`](Reference.md#source)
 
 ### `onMessage`
 
-A function that is invoked when the webview calls `window.postMessage`. Setting this property will inject a `postMessage` global into your webview, but will still call pre-existing values of `postMessage`.
+Function that is invoked when the webview calls `window.ReactNativeWebView.postMessage`. Setting this property will inject this global into your webview.
 
-`window.postMessage` accepts one argument, `data`, which will be available on the event object, `event.nativeEvent.data`. `data` must be a string.
+`window.ReactNativeWebView.postMessage` accepts one argument, `data`, which will be available on the event object, `event.nativeEvent.data`. `data` must be a string.
 
 | Type     | Required |
 | -------- | -------- |

ios/RNCUIWebView.m

 
 NSString *const RNCJSNavigationScheme = @"react-js-navigation";
 
-static NSString *const kPostMessageHost = @"postMessage";
+static NSString *const MessageHandlerName = @"ReactNativeWebView";
 
 @interface RNCUIWebView () <UIWebViewDelegate, RCTAutoInsetsProtocol>
 
     @"data": message,
   };
   NSString *source = [NSString
-    stringWithFormat:@"document.dispatchEvent(new MessageEvent('message', %@));",
+    stringWithFormat:@"window.dispatchEvent(new MessageEvent('message', %@));",
     RCTJSONStringify(eventInitDict, NULL)
   ];
   [_webView stringByEvaluatingJavaScriptFromString:source];
     }
   }
 
-  if (isJSNavigation && [request.URL.host isEqualToString:kPostMessageHost]) {
+  if (isJSNavigation && [request.URL.host isEqualToString:MessageHandlerName]) {
     NSString *data = request.URL.query;
     data = [data stringByReplacingOccurrencesOfString:@"+" withString:@" "];
     data = [data stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
       @"data": data,
     }];
 
-    NSString *source = @"document.dispatchEvent(new MessageEvent('message:received'));";
+    NSString *source = [NSString stringWithFormat:@"window.%@.messageReceived();", MessageHandlerName];
 
     [_webView stringByEvaluatingJavaScriptFromString:source];
 
 - (void)webViewDidFinishLoad:(UIWebView *)webView
 {
   if (_messagingEnabled) {
-    #if RCT_DEV
-    // See isNative in lodash
-    NSString *testPostMessageNative = @"String(window.postMessage) === String(Object.hasOwnProperty).replace('hasOwnProperty', 'postMessage')";
-    BOOL postMessageIsNative = [
-      [webView stringByEvaluatingJavaScriptFromString:testPostMessageNative]
-      isEqualToString:@"true"
-    ];
-    if (!postMessageIsNative) {
-      RCTLogError(@"Setting onMessage on a WebView overrides existing values of window.postMessage, but a previous value was defined");
-    }
-    #endif
     NSString *source = [NSString stringWithFormat:
       @"(function() {"
-        "window.originalPostMessage = window.postMessage;"
-
-        "var messageQueue = [];"
-        "var messagePending = false;"
-
-        "function processQueue() {"
-          "if (!messageQueue.length || messagePending) return;"
-          "messagePending = true;"
-          "window.location = '%@://%@?' + encodeURIComponent(messageQueue.shift());"
-        "}"
-
-        "window.postMessage = function(data) {"
-          "messageQueue.push(String(data));"
-          "processQueue();"
-        "};"
-
-        "document.addEventListener('message:received', function(e) {"
-          "messagePending = false;"
-          "processQueue();"
-        "});"
-      "})();", RNCJSNavigationScheme, kPostMessageHost
+       "  var messageQueue = [];"
+       "  var messagePending = false;"
+
+       "  function processQueue () {"
+       "    if (!messageQueue.length || messagePending) return;"
+       "    messagePending = true;"
+       "    document.location = '%@://%@?' + encodeURIComponent(messageQueue.shift());"
+       "  }"
+
+       "  window.%@ = {"
+       "    postMessage: function (data) {"
+       "      messageQueue.push(String(data));"
+       "      processQueue();"
+       "    },"
+       "    messageReceived: function () {"
+       "      messagePending = false;"
+       "      processQueue();"
+       "    }"
+       "  };"
+       "})();", RNCJSNavigationScheme, MessageHandlerName, MessageHandlerName
     ];
     [webView stringByEvaluatingJavaScriptFromString:source];
   }

ios/RNCWKWebView.m

 #import "objc/runtime.h"
 
 static NSTimer *keyboardTimer;
-static NSString *const MessageHanderName = @"ReactNative";
+static NSString *const MessageHandlerName = @"ReactNativeWebView";
 
 // runtime trick to remove WKWebView keyboard default toolbar
 // see: http://stackoverflow.com/questions/19033292/ios-7-uiwebview-keyboard-issue/19042279#19042279
   return self;
 }
 
+/**
+ * See https://stackoverflow.com/questions/25713069/why-is-wkwebview-not-opening-links-with-target-blank/25853806#25853806 for details.
+ */
+- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures
+{
+  if (!navigationAction.targetFrame.isMainFrame) {
+    [webView loadRequest:navigationAction.request];
+  }
+  return nil;
+}
+
 - (void)didMoveToWindow
 {
   if (self.window != nil && _webView == nil) {
       wkWebViewConfig.processPool = [[RNCWKProcessPoolManager sharedManager] sharedProcessPool];
     }
     wkWebViewConfig.userContentController = [WKUserContentController new];
-    [wkWebViewConfig.userContentController addScriptMessageHandler: self name: MessageHanderName];
+
+    if (_messagingEnabled) {
+      [wkWebViewConfig.userContentController addScriptMessageHandler:self name:MessageHandlerName];
+
+      NSString *source = [NSString stringWithFormat:
+        @"window.%@ = {"
+         "  postMessage: function (data) {"
+         "    window.webkit.messageHandlers.%@.postMessage(String(data));"
+         "  }"
+         "};", MessageHandlerName, MessageHandlerName
+      ];
+
+      WKUserScript *script = [[WKUserScript alloc] initWithSource:source injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES];
+      [wkWebViewConfig.userContentController addUserScript:script];
+    }
+
     wkWebViewConfig.allowsInlineMediaPlayback = _allowsInlineMediaPlayback;
 #if WEBKIT_IOS_10_APIS_AVAILABLE
     wkWebViewConfig.mediaTypesRequiringUserActionForPlayback = _mediaPlaybackRequiresUserAction
 - (void)removeFromSuperview
 {
     if (_webView) {
-        [_webView.configuration.userContentController removeScriptMessageHandlerForName:MessageHanderName];
+        [_webView.configuration.userContentController removeScriptMessageHandlerForName:MessageHandlerName];
         [_webView removeObserver:self forKeyPath:@"estimatedProgress"];
         [_webView removeFromSuperview];
         _webView = nil;
 
 /**
  * This method is called whenever JavaScript running within the web view calls:
- *   - window.webkit.messageHandlers.[MessageHanderName].postMessage
+ *   - window.webkit.messageHandlers[MessageHandlerName].postMessage
  */
 - (void)userContentController:(WKUserContentController *)userContentController
        didReceiveScriptMessage:(WKScriptMessage *)message
 
 -(void)setHideKeyboardAccessoryView:(BOOL)hideKeyboardAccessoryView
 {
-
     if (_webView == nil) {
         _savedHideKeyboardAccessoryView = hideKeyboardAccessoryView;
         return;
     }
 
     UIView* subview;
+
     for (UIView* view in _webView.scrollView.subviews) {
         if([[view.class description] hasPrefix:@"WK"])
             subview = view;
 {
   NSDictionary *eventInitDict = @{@"data": message};
   NSString *source = [NSString
-    stringWithFormat:@"document.dispatchEvent(new MessageEvent('message', %@));",
+    stringWithFormat:@"window.dispatchEvent(new MessageEvent('message', %@));",
     RCTJSONStringify(eventInitDict, NULL)
   ];
-  [self evaluateJS: source thenCall: nil];
+  [self injectJavaScript: source];
 }
 
 - (void)layoutSubviews
   }];
 }
 
-
 /**
  * Called when the navigation is complete.
  * @see https://fburl.com/rtys6jlb
 - (void)      webView:(WKWebView *)webView
   didFinishNavigation:(WKNavigation *)navigation
 {
-  if (_messagingEnabled) {
-    #if RCT_DEV
-
-    // Implementation inspired by Lodash.isNative.
-    NSString *isPostMessageNative = @"String(String(window.postMessage) === String(Object.hasOwnProperty).replace('hasOwnProperty', 'postMessage'))";
-    [self evaluateJS: isPostMessageNative thenCall: ^(NSString *result) {
-      if (! [result isEqualToString:@"true"]) {
-        RCTLogError(@"Setting onMessage on a WebView overrides existing values of window.postMessage, but a previous value was defined");
-      }
-    }];
-    #endif
-
-    NSString *source = [NSString stringWithFormat:
-      @"(function() {"
-        "window.originalPostMessage = window.postMessage;"
-
-        "window.postMessage = function(data) {"
-          "window.webkit.messageHandlers.%@.postMessage(String(data));"
-        "};"
-      "})();",
-      MessageHanderName
-    ];
-    [self evaluateJS: source thenCall: nil];
-  }
-
   if (_injectedJavaScript) {
     [self evaluateJS: _injectedJavaScript thenCall: ^(NSString *jsEvaluationValue) {
       NSMutableDictionary *event = [self baseEvent];
       event[@"jsEvaluationValue"] = jsEvaluationValue;
+
       if (self.onLoadingFinish) {
         self.onLoadingFinish(event);
       }

ios/RNCWebView.xcworkspace/contents.xcworkspacedata

-// !$*UTF8*$!
-<?xml version="1.0" encoding="UTF-8"?>
-<Workspace
-   version = "1.0">
-   <FileRef
-      location = "group:RNCWebView.xcodeproj">
-   </FileRef>
-</Workspace>

jest.config.js

+// For a detailed explanation regarding each configuration property, visit:
+// https://jestjs.io/docs/en/configuration.html
+
+module.exports = {
+  // All imported modules in your tests should be mocked automatically
+  // automock: false,
+
+  // Stop running tests after `n` failures
+  // bail: 0,
+
+  // Respect "browser" field in package.json when resolving modules
+  // browser: false,
+
+  // The directory where Jest should store its cached dependency information
+  // cacheDirectory: "/private/var/folders/8f/kgcy219d1dvfvbcqky441_d00000gp/T/jest_dy",
+
+  // Automatically clear mock calls and instances between every test
+  clearMocks: true,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  // collectCoverage: false,
+
+  // An array of glob patterns indicating a set of files for which coverage information should be collected
+  // collectCoverageFrom: null,
+
+  // The directory where Jest should output its coverage files
+  // coverageDirectory: "coverage",
+
+  // An array of regexp pattern strings used to skip coverage collection
+  // coveragePathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // A list of reporter names that Jest uses when writing coverage reports
+  // coverageReporters: [
+  //   "json",
+  //   "text",
+  //   "lcov",
+  //   "clover"
+  // ],
+
+  // An object that configures minimum threshold enforcement for coverage results
+  // coverageThreshold: null,
+
+  // A path to a custom dependency extractor
+  // dependencyExtractor: null,
+
+  // Make calling deprecated APIs throw helpful error messages
+  // errorOnDeprecated: false,
+
+  // Force coverage collection from ignored files usin a array of glob patterns
+  // forceCoverageMatch: [],
+
+  // A path to a module which exports an async function that is triggered once before all test suites
+  // globalSetup: null,
+
+  // A path to a module which exports an async function that is triggered once after all test suites
+  // globalTeardown: null,
+
+  // A set of global variables that need to be available in all test environments
+  // globals: {},
+
+  // An array of directory names to be searched recursively up from the requiring module's location
+  // moduleDirectories: [
+  //   "node_modules"
+  // ],
+
+  // An array of file extensions your modules use
+  // moduleFileExtensions: [
+  //   "js",
+  //   "json",
+  //   "jsx",
+  //   "ts",
+  //   "tsx",
+  //   "node"
+  // ],
+
+  // A map from regular expressions to module names that allow to stub out resources with a single module
+  // moduleNameMapper: {},
+
+  // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+  // modulePathIgnorePatterns: [],
+
+  // Activates notifications for test results
+  // notify: false,
+
+  // An enum that specifies notification mode. Requires { notify: true }
+  // notifyMode: "failure-change",
+
+  // A preset that is used as a base for Jest's configuration
+  preset: "react-native",
+
+  // Run tests from one or more projects
+  // projects: null,
+
+  // Use this configuration option to add custom reporters to Jest
+  // reporters: undefined,
+
+  // Automatically reset mock state between every test
+  // resetMocks: false,
+
+  // Reset the module registry before running each individual test
+  // resetModules: false,
+
+  // A path to a custom resolver
+  // resolver: null,
+
+  // Automatically restore mock state between every test
+  // restoreMocks: false,
+
+  // The root directory that Jest should scan for tests and modules within
+  // rootDir: null,
+
+  // A list of paths to directories that Jest should use to search for files in
+  // roots: [
+  //   "<rootDir>"
+  // ],
+
+  // Allows you to use a custom runner instead of Jest's default test runner
+  // runner: "jest-runner",
+
+  // The paths to modules that run some code to configure or set up the testing environment before each test
+  // setupFiles: [],
+
+  // A list of paths to modules that run some code to configure or set up the testing framework before each test
+  // setupFilesAfterEnv: [],
+
+  // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+  // snapshotSerializers: [],
+
+  // The test environment that will be used for testing
+  testEnvironment: "node",
+
+  // Options that will be passed to the testEnvironment
+  // testEnvironmentOptions: {},
+
+  // Adds a location field to test results
+  // testLocationInResults: false,
+
+  // The glob patterns Jest uses to detect test files
+  // testMatch: [
+  //   "**/__tests__/**/*.[jt]s?(x)",
+  //   "**/?(*.)+(spec|test).[tj]s?(x)"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+  // testPathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // The regexp pattern or array of patterns that Jest uses to detect test files
+  // testRegex: [],
+
+  // This option allows the use of a custom results processor
+  // testResultsProcessor: null,
+
+  // This option allows use of a custom test runner
+  // testRunner: "jasmine2",
+
+  // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
+  // testURL: "http://localhost",
+
+  // Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
+  // timers: "real",
+
+  // A map from regular expressions to paths to transformers
+  // transform: null,
+
+  // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+  // transformIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+  // unmockedModulePathPatterns: undefined,
+
+  // Indicates whether each individual test should be reported during the run
+  // verbose: null,
+
+  // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+  // watchPathIgnorePatterns: [],
+
+  // Whether to use watchman for file crawling
+  // watchman: true,
+};

js/WebView.android.js

         }
         thirdPartyCookiesEnabled={this.props.thirdPartyCookiesEnabled}
         domStorageEnabled={this.props.domStorageEnabled}
-        messagingEnabled={typeof this.props.onMessage === 'function'}
         cacheEnabled={this.props.cacheEnabled}
         onMessage={this.onMessage}
+        messagingEnabled={typeof this.props.onMessage === 'function'}
         overScrollMode={this.props.overScrollMode}
         contentInset={this.props.contentInset}
         automaticallyAdjustContentInsets={

js/WebView.ios.js

       source = { uri: this.props.url };
     }
 
-    const messagingEnabled = typeof this.props.onMessage === 'function';
-
     let NativeWebView = nativeConfig.component;
 
     if (this.props.useWebKit) {
         onLoadingFinish={this._onLoadingFinish}
         onLoadingError={this._onLoadingError}
         onLoadingProgress={this._onLoadingProgress}
-        messagingEnabled={messagingEnabled}
         onMessage={this._onMessage}
+        messagingEnabled={typeof this.props.onMessage === 'function'}
         onShouldStartLoadWithRequest={onShouldStartLoadWithRequest}
         scalesPageToFit={scalesPageToFit}
         allowsInlineMediaPlayback={this.props.allowsInlineMediaPlayback}

js/WebViewShared.js

 const defaultOriginWhitelist = ['http://*', 'https://*'];
 
 const extractOrigin = (url: string): string => {
-  const result = /^[A-Za-z0-9]+:(\/\/)?[^/]*/.exec(url);
+  const result = /^[A-Za-z][A-Za-z0-9\+\-\.]+:(\/\/)?[^/]*/.exec(url);
   return result === null ? '' : result[0];
 };
 
 const originWhitelistToRegex = (originWhitelist: string): string =>
-  escapeStringRegexp(originWhitelist).replace(/\\\*/g, '.*');
+    `^${escapeStringRegexp(originWhitelist).replace(/\\\*/g, '.*')}`;
 
 const passesWhitelist = (compiledWhitelist: Array<string>, url: string) => {
   const origin = extractOrigin(url);

js/WebViewTypes.js

   onNavigationStateChange?: (event: WebViewNavigation) => mixed,
 
   /**
-   * A function that is invoked when the webview calls `window.postMessage`.
-   * Setting this property will inject a `postMessage` global into your
-   * webview, but will still call pre-existing values of `postMessage`.
+   * Function that is invoked when the webview calls `window.ReactNativeWebView.postMessage`.
+   * Setting this property will inject this global into your webview.
    *
-   * `window.postMessage` accepts one argument, `data`, which will be
-   * available on the event object, `event.nativeEvent.data`. `data`
-   * must be a string.
+   * `window.ReactNativeWebView.postMessage` accepts one argument, `data`, which will be
+   * available on the event object, `event.nativeEvent.data`. `data` must be a string.
    */
   onMessage?: (event: WebViewMessageEvent) => mixed,
 

js/__tests__/WebViewShared-test.js

+import { Linking } from 'react-native';
+
+import {
+  defaultOriginWhitelist,
+  createOnShouldStartLoadWithRequest,
+} from '../WebViewShared';
+
+describe('WebViewShared', () => {
+  test('exports defaultOriginWhitelist', () => {
+    expect(defaultOriginWhitelist).toMatchSnapshot();
+  });
+
+  describe('createOnShouldStartLoadWithRequest', () => {
+    const alwaysTrueOnShouldStartLoadWithRequest = (nativeEvent) => {
+      return true;
+    };
+
+    const alwaysFalseOnShouldStartLoadWithRequest = (nativeEvent) => {
+      return false;
+    };
+
+    const loadRequest = jest.fn();
+
+    test('loadRequest is called without onShouldStartLoadWithRequest override', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        defaultOriginWhitelist,
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'https://www.example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenCalledWith(true, 'https://www.example.com/', 1);
+    });
+
+    test('Linking.openURL is called without onShouldStartLoadWithRequest override', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        defaultOriginWhitelist,
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'invalid://example.com/', lockIdentifier: 2 } });
+      expect(Linking.openURL).toHaveBeenCalledWith('invalid://example.com/');
+      expect(loadRequest).toHaveBeenCalledWith(false, 'invalid://example.com/', 2);
+    });
+
+    test('loadRequest with true onShouldStartLoadWithRequest override is called', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        defaultOriginWhitelist,
+        alwaysTrueOnShouldStartLoadWithRequest,
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'https://www.example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'https://www.example.com/', 1);
+    });
+
+    test('Linking.openURL with true onShouldStartLoadWithRequest override is called for links not passing the whitelist', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        defaultOriginWhitelist,
+        alwaysTrueOnShouldStartLoadWithRequest,
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'invalid://example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('invalid://example.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'invalid://example.com/', 1);
+    });
+
+    test('loadRequest with false onShouldStartLoadWithRequest override is called', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        defaultOriginWhitelist,
+        alwaysFalseOnShouldStartLoadWithRequest,
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'https://www.example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(false, 'https://www.example.com/', 1);
+    });
+
+    test('loadRequest with limited whitelist', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+        loadRequest,
+        ['https://*'],
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'https://www.example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'https://www.example.com/', 1);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'http://insecure.com/', lockIdentifier: 2 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('http://insecure.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, 'http://insecure.com/', 2);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'git+https://insecure.com/', lockIdentifier: 3 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('git+https://insecure.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, 'git+https://insecure.com/', 3);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'fakehttps://insecure.com/', lockIdentifier: 4 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('fakehttps://insecure.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, 'fakehttps://insecure.com/', 4);
+    });
+
+    test('loadRequest allows for valid URIs', () => {
+      const onShouldStartLoadWithRequest = createOnShouldStartLoadWithRequest(
+          loadRequest,
+          ['plus+https://*', 'DOT.https://*', 'dash-https://*', '0invalid://*', '+invalid://*'],
+      );
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'plus+https://www.example.com/', lockIdentifier: 1 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'plus+https://www.example.com/', 1);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'DOT.https://www.example.com/', lockIdentifier: 2 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'DOT.https://www.example.com/', 2);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'dash-https://www.example.com/', lockIdentifier: 3 } });
+      expect(Linking.openURL).toHaveBeenCalledTimes(0);
+      expect(loadRequest).toHaveBeenLastCalledWith(true, 'dash-https://www.example.com/', 3);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: '0invalid://www.example.com/', lockIdentifier: 4 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('0invalid://www.example.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, '0invalid://www.example.com/', 4);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: '+invalid://www.example.com/', lockIdentifier: 5 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('+invalid://www.example.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, '+invalid://www.example.com/', 5);
+
+      onShouldStartLoadWithRequest({ nativeEvent: { url: 'FAKE+plus+https://www.example.com/', lockIdentifier: 6 } });
+      expect(Linking.openURL).toHaveBeenLastCalledWith('FAKE+plus+https://www.example.com/');
+      expect(loadRequest).toHaveBeenLastCalledWith(false, 'FAKE+plus+https://www.example.com/', 6);
+    });
+  });
+});

js/__tests__/__snapshots__/WebViewShared-test.js.snap

+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`WebViewShared exports defaultOriginWhitelist 1`] = `
+Array [
+  "http://*",
+  "https://*",
+]
+`;

package.json

     "Thibault Malbranche <malbranche.thibault@gmail.com>"
   ],
   "license": "MIT",
-  "version": "4.0.0",
+  "version": "5.0.2",
   "homepage": "https://github.com/react-native-community/react-native-webview#readme",
   "scripts": {
+    "test:js": "jest",
     "test:ios:flow": "flow check",
     "test:android:flow": "flow check --flowconfig-name .flowconfig.android",
     "ci:publish": "yarn semantic-release",
-    "ci:test": "yarn ci:test:flow",
+    "ci:test": "yarn ci:test:flow && yarn ci:test:js",
     "ci:test:flow": "yarn test:ios:flow && yarn test:android:flow",
+    "ci:test:js": "yarn test:js",
     "semantic-release": "semantic-release"
   },
   "peerDependencies": {
     "fbjs": "^0.8.17"
   },
   "devDependencies": {
+    "@babel/core": "^7.2.2",
     "@semantic-release/git": "7.0.5",
     "@types/react": "^16.4.18",
     "@types/react-native": "^0.57.6",
+    "babel-jest": "^24.0.0",
     "flow-bin": "^0.80.0",
+    "jest": "^24.0.0",
+    "metro-react-native-babel-preset": "^0.51.1",
     "react-native": "^0.57",
     "semantic-release": "15.10.3"
   },