Add types for the flag which determines if a response is going to be sent or not.

Author: nedtwigg

browser-extension/src/entrypoints/background.ts

@@ -5,6 +5,8 @@ import {
   isContentToBackgroundMessage,
   isGetOpenSpotsMessage,
   isSwitchToTabMessage,
+  CLOSE_MESSAGE_PORT,
+  KEEP_PORT_OPEN,
 } from '../lib/messages'
 
 export interface Tab {
@@ -23,7 +25,7 @@ export interface CommentState {
 
 export const openSpots = new JsonMap<TabAndSpot, CommentState>()
 
-export function handleCommentEvent(message: CommentEvent, sender: any): void {
+export function handleCommentEvent(message: CommentEvent, sender: any): boolean {
   if (
     (message.type === 'ENHANCED' || message.type === 'DESTROYED') &&
     sender.tab?.id &&
@@ -33,12 +35,10 @@ export function handleCommentEvent(message: CommentEvent, sender: any): void {
       tabId: sender.tab.id,
       windowId: sender.tab.windowId,
     }
-
     const tabAndSpot: TabAndSpot = {
       spot: message.spot,
       tab,
     }
-
     if (message.type === 'ENHANCED') {
       const commentState: CommentState = {
         drafts: [],
@@ -48,22 +48,26 @@ export function handleCommentEvent(message: CommentEvent, sender: any): void {
       openSpots.set(tabAndSpot, commentState)
     } else if (message.type === 'DESTROYED') {
       openSpots.delete(tabAndSpot)
+    } else {
+      throw new Error(`Unhandled comment event type: ${message.type}`)
     }
   }
+  return CLOSE_MESSAGE_PORT
 }
 
 export function handlePopupMessage(
   message: any,
   _sender: any,
   sendResponse: (response: any) => void,
-): void {
+): typeof CLOSE_MESSAGE_PORT | typeof KEEP_PORT_OPEN {
   if (isGetOpenSpotsMessage(message)) {
     const spots: CommentState[] = []
     for (const [, commentState] of openSpots) {
       spots.push(commentState)
     }
     const response: GetOpenSpotsResponse = { spots }
     sendResponse(response)
+    return KEEP_PORT_OPEN
   } else if (isSwitchToTabMessage(message)) {
     browser.windows
       .update(message.windowId, { focused: true })
@@ -73,17 +77,18 @@ export function handlePopupMessage(
       .catch((error) => {
         console.error('Error switching to tab:', error)
       })
+    return CLOSE_MESSAGE_PORT
+  } else {
+    throw new Error(`Unhandled popup message type: ${message?.type || 'unknown'}`)
   }
 }
 
 export default defineBackground(() => {
   browser.runtime.onMessage.addListener((message: ToBackgroundMessage, sender, sendResponse) => {
     if (isContentToBackgroundMessage(message)) {
-      handleCommentEvent(message, sender)
-      return false
+      return handleCommentEvent(message, sender)
     } else {
-      handlePopupMessage(message, sender, sendResponse)
-      return true
+      return handlePopupMessage(message, sender, sendResponse)
     }
   })
 })

browser-extension/src/lib/messages.ts

@@ -1,5 +1,9 @@
 import type { CommentDraft, CommentEvent, CommentSpot } from './enhancer'
 
+// Message handler response types
+export const CLOSE_MESSAGE_PORT = false as const // No response will be sent
+export const KEEP_PORT_OPEN = true as const // Response will be sent (possibly async)
+
 // Content -> Background messages (already well-typed as CommentEvent)
 export type ContentToBackgroundMessage = CommentEvent