fix(realtime): add presence flag

packages/realtime_client/lib/src/realtime_channel.dart

@@ -130,10 +130,14 @@ class RealtimeChannel {
         if (callback != null) callback(RealtimeSubscribeStatus.closed, null);
       });
 
+      final presenceEnabled =
+          (_bindings['presence']?.isNotEmpty == true) ||
+          (params['config']['presence']['enabled'] == true);
+
       final accessTokenPayload = <String, String>{};
       final config = <String, dynamic>{
         'broadcast': broadcast,
-        'presence': presence,
+        'presence': {...presence, 'enabled': presenceEnabled},
         'postgres_changes':
             _bindings['postgres_changes']?.map((r) => r.filter).toList() ?? [],
         'private': isPrivate == true,

packages/realtime_client/lib/src/types.dart

@@ -148,13 +148,17 @@ class RealtimeChannelConfig {
   /// [key] option is used to track presence payload across clients
   final String key;
 
+  /// Enables presence even without presence bindings
+  final bool enabled;
+
   /// Defines if the channel is private or not and if RLS policies will be used to check data
   final bool private;
 
   const RealtimeChannelConfig({
     this.ack = false,
     this.self = false,
     this.key = '',
+    this.enabled = false,
     this.private = false,
   });
 
@@ -167,6 +171,7 @@ class RealtimeChannelConfig {
         },
         'presence': {
           'key': key,
+          'enabled': enabled,
         },
         'private': private,
       }

packages/realtime_client/test/channel_test.dart

@@ -34,7 +34,7 @@ void main() {
       expect(channel.params, {
         'config': {
           'broadcast': {'ack': false, 'self': false},
-          'presence': {'key': ''},
+          'presence': {'key': '', 'enabled': false},
           'private': false,
         }
       });
@@ -54,7 +54,7 @@ void main() {
       expect(joinPush.payload, {
         'config': {
           'broadcast': {'ack': false, 'self': false},
-          'presence': {'key': ''},
+          'presence': {'key': '', 'enabled': false},
           'private': true,
         },
       });
@@ -386,4 +386,92 @@ void main() {
       expect(leaveCalled, isTrue);
     });
   });
+
+  group('presence enabled', () {
+    setUp(() {
+      socket = RealtimeClient('', timeout: const Duration(milliseconds: 1234));
+    });
+
+    test('should enable presence when config.presence.enabled is true even without bindings', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(enabled: true),
+      );
+
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isTrue);
+    });
+
+    test('should enable presence when presence listeners exist', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(),
+      );
+
+      channel.onPresenceSync((payload) {});
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isTrue);
+    });
+
+    test('should enable presence when both bindings exist and config.presence.enabled is true', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(enabled: true),
+      );
+
+      channel.onPresenceSync((payload) {});
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isTrue);
+    });
+
+    test('should not enable presence when neither bindings exist nor config.presence.enabled is true', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(),
+      );
+
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isFalse);
+    });
+
+    test('should enable presence when join listener exists', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(),
+      );
+
+      channel.onPresenceJoin((payload) {});
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isTrue);
+    });
+
+    test('should enable presence when leave listener exists', () {
+      channel = RealtimeChannel(
+        'topic',
+        socket,
+        params: const RealtimeChannelConfig(),
+      );
+
+      channel.onPresenceLeave((payload) {});
+      channel.subscribe();
+
+      final joinPayload = channel.joinPush.payload;
+      expect(joinPayload['config']['presence']['enabled'], isTrue);
+    });
+  });
 }