Add additional comments

ext/src/lib/TypedEventTarget.ts

@@ -4,6 +4,9 @@ interface TypedEvents {
     [key: string]: any;
 }
 
+/**
+ * Provides a typed interface to EventTarget objects.
+ */
 export class TypedEventTarget<T extends TypedEvents> extends EventTarget {
     // @ts-ignore
     public addEventListener<K extends keyof T>(

ext/src/lib/TypedMessagePort.ts

@@ -1,5 +1,8 @@
 "use strict";
 
+/**
+ * Provides a typed interface to MessagePort objects.
+ */
 export interface TypedMessagePort<T> extends MessagePort {
     postMessage(message: T, transfer: Transferable[]): void;
     postMessage(message: T, options?: PostMessageOptions): void;

ext/src/lib/TypedPort.ts

@@ -1,7 +1,7 @@
 "use strict";
 
 /**
- * Allows typed access to a runtime.Port object.
+ * Provides a typed interface to runtime.Port objects.
  */
 export interface TypedPort<T>
         extends Omit<browser.runtime.Port

ext/src/lib/bridge.ts

@@ -2,20 +2,17 @@
 
 import semver from "semver";
 
-import { TypedPort } from "./TypedPort";
-
 import logger from "./logger";
-import { Message, Port } from "../messaging";
+import { Port } from "../messaging";
 import nativeMessaging from "./nativeMessaging";
 import options from "./options";
 
-import { ReceiverDevice } from "../types";
-import { ReceiverSelectionCast
-       , ReceiverSelectionStop } from "../background/receiverSelector/ReceiverSelector";
-
 
 export const BRIDGE_TIMEOUT = 5000;
 
+/**
+ * Creates a bridge instance and returns a message port.
+ */
 async function connect(): Promise<Port> {
     const applicationName = await options.get("bridgeApplicationName");
     const bridgePort = nativeMessaging.connectNative(applicationName) as
@@ -47,6 +44,12 @@ export interface BridgeInfo {
 export class BridgeConnectionError extends Error {}
 export class BridgeTimedOutError extends Error {}
 
+/**
+ * Creates a temporary bridge to query the version info,
+ * compares the version to the extension version using semver
+ * rules to determine compatiblity, then returns a
+ * BridgeInfo object.
+ */
 const getInfo = () => new Promise<BridgeInfo>(async (resolve, reject) => {
     const applicationName = await options.get("bridgeApplicationName");
     if (!applicationName) {

ext/src/lib/endpoints.ts

@@ -1,33 +1,32 @@
 "use strict";
 
 /**
- * Cast sender API loader script URL.
+ * Cast Chrome Sender SDK loader script.
  *
- * Since the actual cast sender API script is hosted locally
- * within Chrome, this script just acts a loader script for
- * the real script whilst also doing some UA string
- * checking.
+ * Since the actual SDK script is hosted locally within Chrome,
+ * this script just acts a loader script whilst also doing some
+ * UA string checking.
  */
 export const CAST_LOADER_SCRIPT_URL =
         "https://www.gstatic.com/cv/js/sender/v1/cast_sender.js";
 
 /**
- * Framework API loader script URL.
+ * Cast Chrome Sender Framework API loader script.
  *
  * Same URL as the usual loader script, but the additional
  * search parameter is checked from within the script and
  * the framework API script is conditionally loaded in
- * addition to the regular API script.
+ * addition to the regular SDK script.
  */
 export const CAST_FRAMEWORK_LOADER_SCRIPT_URL =
         `${CAST_LOADER_SCRIPT_URL}?loadCastFramework=1`;
 
 /**
- * Cast API script URLs.
+ * Cast extension URLs.
  *
  * Cast functionality in Chrome was previously provided by
- * an extension. The cast API script is still provided via
- * chrome-extension URLs for compatibility reasons.
+ * an extension. The cast SDK scripts are still provided via
+ * chrome-extension: URLs for compatibility reasons (?).
  */
 export const CAST_SCRIPT_URLS = [
     "chrome-extension://pkedcjkdefgpdelpbcmbmeomcjbeemfm/cast_sender.js"
@@ -35,11 +34,11 @@ export const CAST_SCRIPT_URLS = [
 ];
 
 /**
- * Framework API script URL.
+ * Cast Chrome Sender Framework API script.
  *
- * Unlike the basic cast sender API, the framework API is
- * not hosted locally within Chrome and is the only script
- * fetched directly from Google servers.
+ * The Cast Application Framework (CAF) is implemented as a
+ * wrapper around the base SDK, and ditributed remotely, as
+ * opposed to within the cast extension.
  */
 export const CAST_FRAMEWORK_SCRIPT_URL =
         "https://www.gstatic.com/cast/sdk/libs/sender/1.0/cast_framework.js";