From dec13f8c9c2413e86ddecb84d3433891b6ea37b4 Mon Sep 17 00:00:00 2001
From: Harrison Healey <harrisonmhealey@gmail.com>
Date: Mon, 14 Aug 2023 17:41:22 -0400
Subject: [PATCH] MM-49063 Silence warning when lastViewedAt is undefined
 (#24252)

* MM-49063 Silence warning when lastViewedAt is undefined

* Fix type error
---
 .../channels/src/components/post_view/post_list/index.tsx  | 7 +++++--
 webapp/channels/src/components/post_view/post_view.tsx     | 4 ++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/webapp/channels/src/components/post_view/post_list/index.tsx b/webapp/channels/src/components/post_view/post_list/index.tsx
index 3d532d1eef..72d44e02ad 100644
--- a/webapp/channels/src/components/post_view/post_list/index.tsx
+++ b/webapp/channels/src/components/post_view/post_list/index.tsx
@@ -36,7 +36,7 @@ const memoizedGetLatestPostId = memoizeResult((postIds: string[]) => getLatestPo
 
 interface Props {
     focusedPostId?: string;
-    unreadChunkTimeStamp: number;
+    unreadChunkTimeStamp?: number;
     changeUnreadChunkTimeStamp: (lastViewedAt: number) => void;
     channelId: string;
 }
@@ -75,7 +75,10 @@ function makeMapStateToProps() {
             atOldestPost = Boolean(chunk.oldest);
         }
 
-        const shouldHideNewMessageIndicator = shouldStartFromBottomWhenUnread && !isPostsChunkIncludingUnreadsPosts(state, chunk!, unreadChunkTimeStamp);
+        let shouldHideNewMessageIndicator = false;
+        if (unreadChunkTimeStamp != null) {
+            shouldHideNewMessageIndicator = shouldStartFromBottomWhenUnread && !isPostsChunkIncludingUnreadsPosts(state, chunk!, unreadChunkTimeStamp);
+        }
 
         if (postIds) {
             formattedPostIds = preparePostIdsForPostList(state, {postIds, lastViewedAt, indicateNewMessages: !shouldHideNewMessageIndicator});
diff --git a/webapp/channels/src/components/post_view/post_view.tsx b/webapp/channels/src/components/post_view/post_view.tsx
index 6bf78f3baa..a3fab27647 100644
--- a/webapp/channels/src/components/post_view/post_view.tsx
+++ b/webapp/channels/src/components/post_view/post_view.tsx
@@ -10,7 +10,7 @@ import {Preferences} from 'utils/constants';
 import PostList from './post_list';
 
 interface Props {
-    lastViewedAt: number;
+    lastViewedAt?: number;
     channelLoading: boolean;
     channelId: string;
     focusedPostId?: string;
@@ -18,7 +18,7 @@ interface Props {
 }
 
 interface State {
-    unreadChunkTimeStamp: number;
+    unreadChunkTimeStamp?: number;
     loaderForChangeOfPostsChunk: boolean;
     channelLoading: boolean;
     shouldStartFromBottomWhenUnread: boolean;