From d0d4c4b320632cc6c5a610b6ec22d9305f81396b Mon Sep 17 00:00:00 2001
From: Jamey Huffnagle <jamey.huffnagle@opentrons.com>
Date: Thu, 15 Feb 2024 15:22:57 -0500
Subject: [PATCH] refactor(app): remove notification event emitters

---
 app/src/redux/shell/remote.ts         | 12 +++++-------
 app/src/redux/shell/types.ts          | 10 +++++++++-
 app/src/resources/useNotifyService.ts | 18 ++++--------------
 3 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/app/src/redux/shell/remote.ts b/app/src/redux/shell/remote.ts
index 9671f600e5e..093ae1f4b92 100644
--- a/app/src/redux/shell/remote.ts
+++ b/app/src/redux/shell/remote.ts
@@ -1,10 +1,9 @@
 // access main process remote modules via attachments to `global`
 import assert from 'assert'
-import { EventEmitter } from 'events'
 
 import type { AxiosRequestConfig } from 'axios'
 import type { ResponsePromise } from '@opentrons/api-client'
-import type { Remote, NotifyTopic } from './types'
+import type { Remote, NotifyTopic, NotifyResponseData } from './types'
 
 const emptyRemote: Remote = {} as any
 
@@ -40,16 +39,15 @@ export function appShellRequestor<Data>(
 
 export function appShellListener(
   hostname: string | null,
-  topic: NotifyTopic
-): EventEmitter {
-  const eventEmitter = new EventEmitter()
+  topic: NotifyTopic,
+  listenerCb: (data: NotifyResponseData) => void
+): void {
   remote.ipcRenderer.on(
     'notify',
     (_, shellHostname, shellTopic, shellMessage) => {
       if (hostname === shellHostname && topic === shellTopic) {
-        eventEmitter.emit('data', shellMessage)
+        listenerCb(shellMessage)
       }
     }
   )
-  return eventEmitter
 }
diff --git a/app/src/redux/shell/types.ts b/app/src/redux/shell/types.ts
index 874b98296ef..e2baffba65f 100644
--- a/app/src/redux/shell/types.ts
+++ b/app/src/redux/shell/types.ts
@@ -12,13 +12,21 @@ export interface Remote {
         event: IpcMainEvent,
         hostname: string,
         topic: NotifyTopic,
-        message: string | Object,
+        message: NotifyResponseData | NotifyNetworkError,
         ...args: unknown[]
       ) => void
     ) => void
   }
 }
 
+interface NotifyRefetchData {
+  refetchUsingHTTP: boolean
+  statusCode: never
+}
+
+export type NotifyNetworkError = 'ECONNFAILED' | 'ECONNREFUSED'
+export type NotifyResponseData = NotifyRefetchData | NotifyNetworkError
+
 interface File {
   sha512: string
   url: string
diff --git a/app/src/resources/useNotifyService.ts b/app/src/resources/useNotifyService.ts
index 87398f4bc50..05a73337cae 100644
--- a/app/src/resources/useNotifyService.ts
+++ b/app/src/resources/useNotifyService.ts
@@ -12,22 +12,13 @@ import {
 } from '../redux/analytics'
 
 import type { UseQueryOptions } from 'react-query'
-import type { NotifyTopic } from '../redux/shell/types'
+import type { NotifyTopic, NotifyResponseData } from '../redux/shell/types'
 
 export interface QueryOptionsWithPolling<TData, TError = Error>
   extends UseQueryOptions<TData, TError> {
   forceHttpPolling?: boolean
 }
 
-interface NotifyRefetchData {
-  refetchUsingHTTP: boolean
-  statusCode: never
-}
-
-export type NotifyNetworkError = 'ECONNFAILED' | 'ECONNREFUSED'
-
-type NotifyResponseData = NotifyRefetchData | NotifyNetworkError
-
 interface UseNotifyServiceProps<TData, TError = Error> {
   topic: NotifyTopic
   refetchUsingHTTP: () => void
@@ -55,12 +46,11 @@ export function useNotifyService<TData, TError = Error>({
       hostname != null &&
       staleTime !== Infinity
     ) {
-      const eventEmitter = appShellListener(hostname, topic)
-      eventEmitter.on('data', onDataListener)
+      const listenerCb = (data: NotifyResponseData): void => onDataEvent(data)
+      appShellListener(hostname, topic, listenerCb)
       dispatch(notifySubscribeAction(hostname, topic))
 
       return () => {
-        eventEmitter.off('data', onDataListener)
         if (hostname != null) {
           dispatch(notifyUnsubscribeAction(hostname, topic))
         }
@@ -77,7 +67,7 @@ export function useNotifyService<TData, TError = Error>({
 
   return { isNotifyError: isNotifyError.current }
 
-  function onDataListener(data: NotifyResponseData): void {
+  function onDataEvent(data: NotifyResponseData): void {
     if (!isNotifyError.current) {
       if (data === 'ECONNFAILED' || data === 'ECONNREFUSED') {
         isNotifyError.current = true