fix: queue channel WS events until the channel is initialized

src/channel.ts

@@ -89,6 +89,12 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
   lastTypingEvent: Date | null;
   isTyping: boolean;
   disconnected: boolean;
+  /**
+   * Collects the incoming WS events before the channel is marked as initialized.
+   * This prevents executing procedures that depend on channel being initialized.
+   * Once the channel is marked as initialized the queue is flushed.
+   */
+  wsEventQueue: Event<StreamChatGenerics>[];
 
   /**
    * constructor - Create a channel
@@ -132,6 +138,7 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
     this.lastTypingEvent = null;
     this.isTyping = false;
     this.disconnected = false;
+    this.wsEventQueue = [];
   }
 
   /**
@@ -780,6 +787,7 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
     const combined = { ...defaultOptions, ...options };
     const state = await this.query(combined, 'latest');
     this.initialized = true;
+    this._flushWsEventQueue();
     this.data = state.channel;
 
     this._client.logger('info', `channel:watch() - started watching channel ${this.cid}`, {
@@ -1207,6 +1215,12 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
   // eslint-disable-next-line sonarjs/cognitive-complexity
   _handleChannelEvent(event: Event<StreamChatGenerics>) {
     const channel = this;
+
+    if (!this._isInitialized()) {
+      this.wsEventQueue.push(event);
+      return;
+    }
+
     this._client.logger(
       'info',
       `channel:_handleChannelEvent - Received event of type { ${event.type} } on ${this.cid}`,
@@ -1442,6 +1456,10 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
     return `${this.getClient().baseURL}/channels/${this.type}/${this.id}`;
   };
 
+  _isInitialized() {
+    return this.initialized || this.offlineMode || this.getClient()._isUsingServerAuth();
+  }
+
   _checkInitialized() {
     if (!this.initialized && !this.offlineMode && !this.getClient()._isUsingServerAuth()) {
       throw Error(
@@ -1555,4 +1573,11 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
     this.disconnected = true;
     this.state.setIsUpToDate(false);
   }
+
+  _flushWsEventQueue() {
+    while (this.wsEventQueue.length) {
+      const event = this.wsEventQueue.shift();
+      if (event) this.getClient().dispatchEvent(event);
+    }
+  }
 }

src/events.ts

@@ -47,3 +47,28 @@ export const EVENT_MAP = {
   'connection.recovered': true,
   'transport.changed': true,
 };
+
+// events handled by channel._handleChannelEvent
+export const CHANNEL_HANDLED_EVENTS = {
+  'typing.start': true,
+  'typing.stop': true,
+  'message.read': true,
+  'user.watching.start': true,
+  'user.updated': true,
+  'user.watching.stop': true,
+  'message.deleted': true,
+  'message.new': true,
+  'message.updated': true,
+  'channel.truncated': true,
+  'member.added': true,
+  'member.updated': true,
+  'member.removed': true,
+  'channel.updated': true,
+  'reaction.new': true,
+  'reaction.deleted': true,
+  'reaction.updated': true,
+  'channel.hidden': true,
+  'channel.visible': true,
+  'user.banned': true,
+  'user.unbanned': true,
+};

test/unit/channel.js

@@ -1,4 +1,5 @@
 import chai from 'chai';
+import sinon from 'sinon';
 import { v4 as uuidv4 } from 'uuid';
 
 import { generateChannel } from './test-utils/generateChannel';
@@ -8,8 +9,7 @@ import { generateUser } from './test-utils/generateUser';
 import { getClientWithUser } from './test-utils/getClient';
 import { getOrCreateChannelApi } from './test-utils/getOrCreateChannelApi';
 
-import { StreamChat } from '../../src/client';
-import { ChannelState } from '../../src';
+import { CHANNEL_HANDLED_EVENTS, ChannelState, StreamChat } from '../../src';
 
 const expect = chai.expect;
 
@@ -497,6 +497,76 @@ describe('Channel _handleChannelEvent', function () {
 			expect(channel.state.members[user.id].shadow_banned).eq(expectAfterSecond.shadow_banned);
 		});
 	});
+
+	const eventTypes = Object.keys(CHANNEL_HANDLED_EVENTS);
+	const receiveAllChannelEvents = (channel) => {
+		eventTypes.forEach((type) => {
+			channel._handleChannelEvent({ type });
+		});
+	};
+
+	it('buffers WS events when uninitialized', () => {
+		channel.initialized = false;
+		channel.offlineMode = false;
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.have.length(eventTypes.length);
+	});
+
+	it('does not buffer WS events when in offline mode', () => {
+		channel.initialized = false;
+		channel.offlineMode = true;
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.be.empty;
+	});
+
+	it('does not buffer WS events with server-side client', () => {
+		client = new StreamChat('apiKey', 'secret');
+		client.user = user;
+		client.userID = user.id;
+		channel = client.channel('messaging', 'id');
+		channel.initialized = false;
+		channel.offlineMode = false;
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.be.empty;
+	});
+
+	it('does not buffer WS events on initialized channel', () => {
+		channel.initialized = true;
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.be.empty;
+	});
+
+	it('buffers WS events and channel.watch() flushes upon channel initialization', async () => {
+		channel.initialized = false;
+		sinon.stub(client, 'doAxiosRequest').resolves({ channel: generateChannel(), members: [] });
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.have.length(eventTypes.length);
+		await channel.watch();
+		expect(channel.wsEventQueue).to.be.empty;
+		client.doAxiosRequest.restore();
+	});
+
+	it('buffers WS events and channel.query() does not flush the queue', async () => {
+		channel.initialized = false;
+		sinon.stub(client, 'doAxiosRequest').resolves({ channel: generateChannel(), members: [] });
+
+		receiveAllChannelEvents(channel);
+
+		expect(channel.wsEventQueue).to.have.length(eventTypes.length);
+		await channel.query();
+		expect(channel.wsEventQueue).to.have.length(eventTypes.length);
+		client.doAxiosRequest.restore();
+	});
 });
 
 describe('Channels - Constructor', function () {

test/unit/channel_state.js

@@ -645,6 +645,7 @@ describe('ChannelState clean', () => {
 		client.userID = 'observer';
 		channel = new Channel(client, 'live', 'stream', {});
 		client.activeChannels[channel.cid] = channel;
+		channel.initialized = true;
 	});
 
 	it('should remove any stale typing events with either string or Date received_at', async () => {