Convert shim to Typescript (#32)

ext/src/shim/content.ts

@@ -0,0 +1,34 @@
+"use strict";
+
+import { Message } from "../types";
+import { onMessageResponse, sendMessage } from "./messageBridge";
+
+// Message ports
+const backgroundPort = browser.runtime.connect({ name: "shim" });
+let popupPort: browser.runtime.Port;
+
+
+// Set popupPort once it connects
+browser.runtime.onConnect.addListener(port => {
+    if (port.name === "popup") {
+        popupPort = port;
+    }
+
+    port.onMessage.addListener(sendMessage);
+});
+
+// Forward background messages to shim
+backgroundPort.onMessage.addListener(sendMessage);
+
+// Forward shim messages to popup and background script
+onMessageResponse((message: Message) => {
+    const [ destination ] = message.subject.split(":/");
+
+    if (destination === "popup") {
+        if (popupPort) {
+            popupPort.postMessage(message);
+        }
+    } else {
+        backgroundPort.postMessage(message);
+    }
+});