Merge pull request #1448 from GetStream/ISSUE-1432/FIxingWatchersStream

packages/stream_chat/CHANGELOG.md

@@ -1,5 +1,10 @@
 ## Upcoming
 
+🐞 Fixed
+
+- Fixed streamWatchers. Before it was always new, now it is possible to follow the watchers of a channel. 
+## Upcoming
+
 🔄 Changed
 
 - Cancelling a attachment upload now removes the attachment from the message.

packages/stream_chat/lib/src/client/channel.dart

@@ -1628,6 +1628,10 @@ class ChannelClientState {
 
     _listenMemberUnbanned();
 
+    _listenUserStartWatching();
+
+    _listenUserStopWatching();
+
     _startCleaningStaleTypingEvents();
 
     _startCleaningStalePinnedMessages();
@@ -1769,6 +1773,39 @@ class ChannelClientState {
     ));
   }
 
+  void _listenUserStartWatching() {
+    _subscriptions.add(
+      _channel.on(EventType.userWatchingStart).listen((event) {
+        final watcher = event.user;
+        if (watcher != null) {
+          final existingWatchers = channelState.watchers;
+          updateChannelState(channelState.copyWith(
+            watchers: [
+              ...?existingWatchers,
+              watcher,
+            ],
+          ));
+        }
+      }),
+    );
+  }
+
+  void _listenUserStopWatching() {
+    _subscriptions.add(
+      _channel.on(EventType.userWatchingStop).listen((event) {
+        final watcher = event.user;
+        if (watcher != null) {
+          final existingWatchers = channelState.watchers;
+          updateChannelState(channelState.copyWith(
+            watchers: existingWatchers
+                ?.where((user) => user.id != watcher.id)
+                .toList(growable: false),
+          ));
+        }
+      }),
+    );
+  }
+
   void _listenMemberUnbanned() {
     _subscriptions.add(_channel
         .on(EventType.userUnbanned)
@@ -2098,7 +2135,7 @@ class ChannelClientState {
         channelStateStream.map((cs) => cs.watchers),
         _channel.client.state.usersStream,
         (watchers, users) => watchers!.map((e) => users[e.id] ?? e).toList(),
-      );
+      ).distinct(const ListEquality().equals);
 
   /// Channel member for the current user.
   Member? get currentUserMember => members.firstWhereOrNull(

packages/stream_chat/lib/src/event_type.dart

@@ -36,6 +36,12 @@ class EventType {
   /// Event sent when updating a message
   static const String messageUpdated = 'message.updated';
 
+  /// Event sent when a user starts watching a channel
+  static const String userWatchingStart = 'user.watching.start';
+
+  /// Event sent when a user stops watching a channel
+  static const String userWatchingStop = 'user.watching.stop';
+
   /// Event sent when reading a message
   static const String messageRead = 'message.read';