From c34ef129ecbb70ab11066ee0add8f48afecfaa07 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Sun, 22 Jan 2023 18:12:29 +0100
Subject: [PATCH] [Perf] Avoid redundant updates of chat and user `usernames`
 field

---
 src/global/reducers/chats.ts | 22 ++++++++++++++++------
 src/global/reducers/users.ts | 12 +++++++++++-
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/src/global/reducers/chats.ts b/src/global/reducers/chats.ts
index 7dfb3601f..601c2ad81 100644
--- a/src/global/reducers/chats.ts
+++ b/src/global/reducers/chats.ts
@@ -9,6 +9,7 @@ import {
 } from '../../util/iteratees';
 import { selectChat, selectChatListType } from '../selectors';
 import { updateThread, updateThreadInfo } from './messages';
+import { areDeepEqual } from '../../util/areDeepEqual';
 
 export function replaceChatListIds(
   global: GlobalState,
@@ -125,15 +126,24 @@ function getUpdatedChat(
 ) {
   const { byId } = global.chats;
   const chat = byId[chatId];
-  const shouldOmitMinInfo = chatUpdate.isMin && chat && !chat.isMin;
+  const omitProps: (keyof ApiChat)[] = [];
+
+  const shouldOmitMinInfo = chatUpdate.isMin && chat && !chat.isMin;
+  if (shouldOmitMinInfo) {
+    omitProps.push('isMin', 'accessHash');
+  }
+
+  if (!noOmitUnreadReactionCount) {
+    omitProps.push('unreadReactionsCount');
+  }
+
+  if (areDeepEqual(chat?.usernames, chatUpdate.usernames)) {
+    omitProps.push('usernames');
+  }
 
-  chatUpdate = noOmitUnreadReactionCount
-    ? chatUpdate : omit(chatUpdate, ['unreadReactionsCount']);
   const updatedChat: ApiChat = {
     ...chat,
-    ...(shouldOmitMinInfo
-      ? omit(chatUpdate, ['isMin', 'accessHash'])
-      : chatUpdate),
+    ...omit(chatUpdate, omitProps),
     ...(photo && { photos: [photo, ...(chat.photos || [])] }),
   };
 
diff --git a/src/global/reducers/users.ts b/src/global/reducers/users.ts
index 9f71af591..cac6bd5ec 100644
--- a/src/global/reducers/users.ts
+++ b/src/global/reducers/users.ts
@@ -4,6 +4,7 @@ import type { ApiUser, ApiUserStatus } from '../../api/types';
 import { omit, pick } from '../../util/iteratees';
 import { MEMO_EMPTY_ARRAY } from '../../util/memo';
 import { updateChat } from './chats';
+import { areDeepEqual } from '../../util/areDeepEqual';
 
 export function replaceUsers(global: GlobalState, newById: Record<string, ApiUser>): GlobalState {
   return {
@@ -109,11 +110,20 @@ export function addUsers(global: GlobalState, newById: Record<string, ApiUser>):
 function getUpdatedUser(global: GlobalState, userId: string, userUpdate: Partial<ApiUser>) {
   const { byId } = global.users;
   const user = byId[userId];
+  const omitProps: (keyof ApiUser)[] = [];
+
   const shouldOmitMinInfo = userUpdate.isMin && user && !user.isMin;
+  if (shouldOmitMinInfo) {
+    omitProps.push('isMin', 'accessHash');
+  }
+
+  if (areDeepEqual(user?.usernames, userUpdate.usernames)) {
+    omitProps.push('usernames');
+  }
 
   const updatedUser = {
     ...user,
-    ...(shouldOmitMinInfo ? omit(userUpdate, ['isMin', 'accessHash']) : userUpdate),
+    ...omit(userUpdate, omitProps),
   };
 
   if (!updatedUser.id || !updatedUser.type) {