fix: skip channel.state.last_message_at update on incoming system message if configured

src/channel_state.ts

@@ -250,11 +250,15 @@ export class ChannelState {
           delete this.threads[message.id];
         }
 
-        if (!this.last_message_at) {
-          this.last_message_at = new Date(message.created_at.getTime());
-        }
-
-        if (message.created_at.getTime() > this.last_message_at.getTime()) {
+        const shouldSkipLastMessageAtUpdate =
+          this._channel.getConfig()?.skip_last_msg_update_for_system_msgs &&
+          message.type === 'system';
+
+        if (
+          !shouldSkipLastMessageAtUpdate &&
+          (!this.last_message_at ||
+            message.created_at.getTime() > this.last_message_at.getTime())
+        ) {
           this.last_message_at = new Date(message.created_at.getTime());
         }
       }

src/types.ts

@@ -2403,6 +2403,7 @@ export type ChannelConfigFields = {
   replies?: boolean;
   search?: boolean;
   shared_locations?: boolean;
+  skip_last_msg_update_for_system_msgs?: boolean;
   count_messages?: boolean;
   typing_events?: boolean;
   uploads?: boolean;

test/unit/channel.test.js

@@ -1687,11 +1687,16 @@ describe('Channel search', async () => {
 });
 
 describe('Channel lastMessage', async () => {
-	const client = await getClientWithUser();
-	const channel = client.channel('messaging', uuidv4());
+	let channel;
+	let client;
+	beforeEach(async () => {
+		client = await getClientWithUser();
+		channel = client.channel('messaging', uuidv4());
+		client._addChannelConfig({ cid: channel.cid, config: {} });
+	});
 
 	it('should return last message - messages are in order', () => {
-		channel.state = new ChannelState();
+		channel.state = new ChannelState(channel);
 		const latestMessageDate = '2018-01-01T00:13:24';
 		channel.state.addMessagesSorted([
 			generateMsg({ date: '2018-01-01T00:00:00' }),
@@ -1705,7 +1710,7 @@ describe('Channel lastMessage', async () => {
 	});
 
 	it('should return last message - messages are out of order', () => {
-		channel.state = new ChannelState();
+		channel.state = new ChannelState(channel);
 		const latestMessageDate = '2018-01-01T00:13:24';
 		channel.state.addMessagesSorted([
 			generateMsg({ date: latestMessageDate }),
@@ -1719,7 +1724,7 @@ describe('Channel lastMessage', async () => {
 	});
 
 	it('should return last message - state has more message sets loaded', () => {
-		channel.state = new ChannelState();
+		channel.state = new ChannelState(channel);
 		const latestMessageDate = '2018-01-01T00:13:24';
 		const latestMessages = [
 			generateMsg({ date: latestMessageDate }),
@@ -1737,6 +1742,30 @@ describe('Channel lastMessage', async () => {
 			new Date(latestMessageDate).getTime(),
 		);
 	});
+
+	it('should return last message - system message is ignored when skip_last_msg_update_for_system_msgs: true', () => {
+		client._addChannelConfig({
+			cid: channel.cid,
+			config: { skip_last_msg_update_for_system_msgs: true },
+		});
+		channel.state = new ChannelState(channel);
+		const latestMessageDate = '2018-01-01T00:13:24';
+		const latestMessages = [
+			generateMsg({ date: latestMessageDate, type: 'system' }),
+			generateMsg({ date: '2018-01-01T00:02:00' }),
+			generateMsg({ date: '2018-01-01T00:00:00' }),
+		];
+		const otherMessages = [
+			generateMsg({ date: '2017-11-21T00:05:33' }),
+			generateMsg({ date: '2017-11-21T00:05:35' }),
+		];
+		channel.state.addMessagesSorted(latestMessages);
+		channel.state.addMessagesSorted(otherMessages, 'new');
+
+		expect(channel.state.last_message_at.getTime()).toBe(
+			new Date(latestMessages[1].created_at).getTime(),
+		);
+	});
 });
 
 describe('Channel _initializeState', () => {