Split status listener handling into class

app/src/StatusListener.ts

@@ -0,0 +1,80 @@
+"use strict";
+
+import { Channel, Client } from "castv2";
+import { EventEmitter } from "events";
+
+const NS_CONNECTION = "urn:x-cast:com.google.cast.tp.connection";
+const NS_HEARTBEAT = "urn:x-cast:com.google.cast.tp.heartbeat";
+const NS_RECEIVER = "urn:x-cast:com.google.cast.receiver";
+
+
+/**
+ * Creates a connection to a receiver device and forwards
+ * RECEIVER_STATUS updates to the extension.
+ */
+export default class StatusListener extends EventEmitter {
+    private client: Client;
+    private clientReceiver: Channel;
+    private clientHeartbeatIntervalId: number;
+
+    constructor (
+            private host: string
+          , private port: number) {
+
+        super();
+
+        this.client = new Client();
+        this.client.connect({ host, port }, this.onConnect.bind(this));
+
+        this.client.on("close", () => {
+            clearInterval(this.clientHeartbeatIntervalId);
+        });
+    }
+
+    /**
+     * Closes status listener connection.
+     */
+    public deregister (): void {
+        this.clientReceiver.send({ type: "CLOSE" });
+        this.client.close();
+    }
+
+
+    private onConnect (): void {
+        const sourceId = "sender-0";
+        const destinationId = "receiver-0";
+
+        const clientConnection = this.client.createChannel(
+                sourceId, destinationId, NS_CONNECTION, "JSON");
+        const clientHeartbeat = this.client.createChannel(
+                sourceId, destinationId, NS_HEARTBEAT, "JSON");
+        const clientReceiver = this.client.createChannel(
+                sourceId, destinationId, NS_RECEIVER, "JSON");
+
+        clientReceiver.on("message", data => {
+            switch (data.type) {
+                case "CLOSE": {
+                    this.client.close();
+                    break;
+                }
+
+                case "RECEIVER_STATUS": {
+                    // Send update message
+                    this.emit("statusUpdate", data.status);
+
+                    break;
+                }
+            }
+        });
+
+        clientConnection.send({ type: "CONNECT" });
+        clientHeartbeat.send({ type: "PING" });
+        clientReceiver.send({ type: "GET_STATUS", requestId: 1 });
+
+        this.clientReceiver = clientReceiver;
+
+        this.clientHeartbeatIntervalId = setInterval(() => {
+            clientHeartbeat.send({ type: "PING" });
+        });
+    }
+}

app/src/main.ts

@@ -8,21 +8,15 @@ import path from "path";
 
 import Media from "./Media";
 import Session from "./Session";
+import StatusListener from "./StatusListener";
 import * as transforms from "./transforms";
 
-import { Channel, Client } from "castv2";
-
 import { Message } from "./types";
 
 import { __applicationName
        , __applicationVersion } from "../package.json";
 
 
-const NS_CONNECTION = "urn:x-cast:com.google.cast.tp.connection";
-const NS_HEARTBEAT = "urn:x-cast:com.google.cast.tp.heartbeat";
-const NS_RECEIVER = "urn:x-cast:com.google.cast.receiver";
-
-
 // Increase listener limit
 events.EventEmitter.defaultMaxListeners = 50;
 
@@ -188,13 +182,24 @@ async function handleMessage (message: Message) {
 }
 
 function initialize (options: InitializeOptions) {
+    const statusListeners = new Map<string, StatusListener>();
+
     browser.on("serviceUp", (service: dnssd.Service) => {
         const address = service.addresses[0];
         const port = service.port;
         const id = service.txt.id;
 
         if (options.shouldWatchStatus) {
-            registerStatusListener(address, port, id);
+            const listener = new StatusListener(address, port);
+
+            listener.on("statusUpdate", (status: any) => {
+                sendMessage({
+                    subject: "main:/receiverStatusUpdate"
+                  , data: { id, status }
+                });
+            });
+
+            statusListeners.set(id, listener);
         }
 
         transforms.encode.write({
@@ -210,8 +215,8 @@ function initialize (options: InitializeOptions) {
     browser.on("serviceDown", (service: dnssd.Service) => {
         const id = service.txt.id;
 
-        if (options.shouldWatchStatus) {
-            deregisterStatusListener(id);
+        if (options.shouldWatchStatus && statusListeners.has(id)) {
+            statusListeners.get(id).deregister();
         }
 
         transforms.encode.write({
@@ -222,93 +227,3 @@ function initialize (options: InitializeOptions) {
 
     browser.start();
 }
-
-
-interface StatusListener {
-    client: Client;
-    clientReceiver: Channel;
-}
-
-// Map of client connections
-const statusListeners = new Map<string, StatusListener>();
-
-/**
- * Creates a connection to a receiver device and forwards
- * RECEIVER_STATUS updates to the extension.
- */
-function registerStatusListener (
-        host: string
-      , port: number
-      , id: string) {
-
-    const client = new Client();
-
-    const sourceId = "sender-0";
-    const destinationId = "receiver-0";
-
-    let heartbeatIntervalId: number;
-
-    client.connect({ host, port }, () => {
-        const clientConnection = client.createChannel(
-                sourceId, destinationId, NS_CONNECTION, "JSON");
-        const clientHeartbeat = client.createChannel(
-                sourceId, destinationId, NS_HEARTBEAT, "JSON");
-        const clientReceiver = client.createChannel(
-                sourceId, destinationId, NS_RECEIVER, "JSON");
-
-
-        clientReceiver.on("message", data => {
-            switch (data.type) {
-                case "CLOSE": {
-                    client.close();
-                    break;
-                }
-
-                case "RECEIVER_STATUS": {
-                    // Send update message
-                    transforms.encode.write({
-                        subject: "main:/receiverStatusUpdate"
-                      , data: {
-                            id
-                          , status: data.status
-                        }
-                    });
-
-                    break;
-                }
-            }
-        });
-
-        clientConnection.send({ type: "CONNECT" });
-        clientHeartbeat.send({ type: "PING" });
-        clientReceiver.send({ type: "GET_STATUS", requestId: 1 });
-
-        heartbeatIntervalId = setInterval(() => {
-            clientHeartbeat.send({ type: "PING" });
-        });
-
-        statusListeners.set(id, {
-            client
-          , clientReceiver
-        });
-    });
-
-    client.on("close", () => {
-        clearInterval(heartbeatIntervalId);
-    });
-}
-
-/**
- * Closes status listener connection for a given receiver
- * device.
- */
-function deregisterStatusListener (id: string) {
-    const { client, clientReceiver } = statusListeners.get(id);
-
-    // Cleanup
-    clientReceiver.send({ type: "CLOSE" });
-    client.close();
-
-    // Remove from map
-    statusListeners.delete(id);
-}