Add messageRouter

ext/src/messageRouter.js

@@ -0,0 +1,25 @@
+"use strict";
+
+const routeMap = new Map();
+
+
+function register (routeName, senderCallback) {
+    routeMap.set(routeName, senderCallback);
+}
+
+function deregister (routeName) {
+    routeMap.delete(routeName);
+}
+
+function handleMessage (message, sender) {
+    const destination = message.subject.split(":")[0];
+    if (routeMap.has(destination)) {
+        routeMap.get(destination)(message, sender);
+    }
+}
+
+export default {
+    register
+  , deregister
+  , handleMessage
+}