Merge branch 'feature/add-event' into develop

Author: alinz

README.md

@@ -86,17 +86,33 @@ This example can be found in `examples` folder.
 
 ```js
 const injectScript = `
-  (function () {
-    if (WebViewBridge) {
+  function webViewBridgeReady(cb) {
+    //checks whether WebViewBirdge exists in global scope.
+    if (window.WebViewBridge) {
+      cb(window.WebViewBridge);
+      return;
+    }
 
-      WebViewBridge.onMessage = function (message) {
-        alert('got a message from Native: ' + message);
+    function handler() {
+      //remove the handler from listener since we don't need it anymore
+      document.removeEventListener('WebViewBridge', handler, false);
+      //pass the WebViewBridge object to the callback
+      cb(window.WebViewBridge);
+    }
 
-        WebViewBridge.send("message from webview");
-      };
+    //if WebViewBridge doesn't exist in global scope attach itself to document
+    //event system. Once the code is being injected by extension, the handler will
+    //be called.
+    document.addEventListener('WebViewBridge', handler, false);
+  }
 
-    }
-  }());
+  webViewBridgeReady(function (webViewBridge) {
+    WebViewBridge.onMessage = function (message) {
+      alert('got a message from Native: ' + message);
+
+      WebViewBridge.send("message from webview");
+    };
+  });
 `;
 
 var Sample2 = React.createClass({

ios/RCTWebViewBridge.m

@@ -286,6 +286,8 @@ - (NSString *)webViewBridgeScript {
       var RNWBSchema = 'wvb';
       var sendQueue = [];
       var receiveQueue = [];
+      var doc = window.document;
+      var customEvent = doc.createEvent('Event');
 
       function callFunc(func, message) {
         if ('function' === typeof func) {
@@ -340,6 +342,10 @@ function signalNative() {
       };
 
       window.WebViewBridge = WebViewBridge;
+
+      //dispatch event
+      customEvent.initEvent('WebViewBridge', true, true);
+      doc.dispatchEvent(customEvent);
     }(window));
   );
 }

scripts/webviewbridge.js

@@ -9,6 +9,8 @@
   var RNWBSchema = 'wvb';
   var sendQueue = [];
   var receiveQueue = [];
+  var doc = window.document;
+  var customEvent = doc.createEvent('Event');
 
   function callFunc(func, message) {
     if ('function' === typeof func) {
@@ -63,4 +65,8 @@
   };
 
   window.WebViewBridge = WebViewBridge;
+
+  //dispatch event
+  customEvent.initEvent('WebViewBridge', true, true);
+  doc.dispatchEvent(customEvent);
 }(window));