Merge pull request #406 from GetStream/feat/type-safe-filter

[CDS-191] feat(llc): add support for type safe filters

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

@@ -19,19 +19,24 @@ class Channel {
   /// Create a channel client instance.
   Channel(
     this._client,
-    this.type,
+    this._type,
-    this._id,
+    this._id, {
-    this._extraData,
+    Map<String, Object> extraData = const {},
-  ) : _cid = _id != null ? '$type:$_id' : null {
+  })  : _cid = _id != null ? '$_type:$_id' : null,
+        _extraData = extraData {
     _client.logger.info('New Channel instance not initialized created');
   }
 
   /// Create a channel client instance from a [ChannelState] object
-  Channel.fromState(this._client, ChannelState channelState) : _extraData = {} {
+  Channel.fromState(this._client, ChannelState channelState)
-    _cid = channelState.channel!.cid;
+      : assert(
-    _id = channelState.channel!.id;
+          channelState.channel != null,
-    type = channelState.channel!.type;
+          'No channel found inside channel state',
-
+        ),
+        _id = channelState.channel!.id,
+        _type = channelState.channel!.type,
+        _cid = channelState.channel!.cid,
+        _extraData = channelState.channel!.extraData ?? {} {
     state = ChannelClientState(this, channelState);
     _initializedCompleter.complete(true);
     _client.logger.info('New Channel instance initialized created');
@@ -41,19 +46,20 @@ class Channel {
   ChannelClientState? state;
 
   /// The channel type
-  String? type;
+  final String _type;
 
   String? _id;
   String? _cid;
-  Map<String, dynamic> _extraData;
+  final Map<String, dynamic> _extraData;
 
   set extraData(Map<String, dynamic> extraData) {
     if (_initializedCompleter.isCompleted) {
-      throw Exception(
+      throw StateError(
-          'Once the channel is initialized you should use channel.update '
+        'Once the channel is initialized you should use channel.update '
-          'to update channel data');
+        'to update channel data',
+      );
     }
-    _extraData = extraData;
+    _extraData.addAll(extraData);
   }
 
   /// Returns true if the channel is muted
@@ -179,6 +185,9 @@ class Channel {
   /// Channel id
   String? get id => state?._channelState.channel?.id ?? _id;
 
+  /// Channel type
+  String get type => state?._channelState.channel?.type ?? _type;
+
   /// Channel cid
   String? get cid => state?._channelState.channel?.cid ?? _cid;
 
@@ -193,9 +202,11 @@ class Channel {
       state?._channelState.channel?.extraData ?? _extraData;
 
   /// Channel extra data as a stream
-  Stream<Map<String, dynamic>?>? get extraDataStream {
+  Stream<Map<String, dynamic>> get extraDataStream {
     _checkInitialized();
-    return state?.channelStateStream.map((cs) => cs.channel?.extraData);
+    return state!.channelStateStream.map(
+      (cs) => cs.channel?.extraData ?? _extraData,
+    );
   }
 
   /// The main Stream chat client
@@ -384,7 +395,7 @@ class Channel {
         message = await attachmentsUploadCompleter.future;
       }
 
-      final response = await _client.sendMessage(message, id!, type!);
+      final response = await _client.sendMessage(message, id!, type);
       state!.addMessage(response.message);
       return response;
     } catch (error) {
@@ -537,7 +548,7 @@ class Channel {
     return _client.sendFile(
       file,
       id!,
-      type!,
+      type,
       onSendProgress: onSendProgress,
       cancelToken: cancelToken,
     );
@@ -553,7 +564,7 @@ class Channel {
     return _client.sendImage(
       file,
       id!,
-      type!,
+      type,
       onSendProgress: onSendProgress,
       cancelToken: cancelToken,
     );
@@ -565,18 +576,16 @@ class Channel {
     Map<String, dynamic>? messageFilters,
     List<SortOption>? sort,
     PaginationParams? paginationParams,
-  }) =>
+  }) {
-      _client.search(
+    _checkInitialized();
-        {
+    return _client.search(
-          'cid': {
+      Filter.in_('cid', [cid!]),
-            r'$in': [cid],
+      sort: sort,
-          },
+      query: query,
-        },
+      paginationParams: paginationParams,
-        sort: sort,
+      messageFilters: messageFilters,
-        query: query,
+    );
-        paginationParams: paginationParams,
+  }
-        messageFilters: messageFilters,
-      );
 
   /// Delete a file from this channel
   Future<EmptyResponse> deleteFile(
@@ -587,7 +596,7 @@ class Channel {
     return _client.deleteFile(
       url,
       id!,
-      type!,
+      type,
       cancelToken: cancelToken,
     );
   }
@@ -601,7 +610,7 @@ class Channel {
     return _client.deleteImage(
       url,
       id!,
-      type!,
+      type,
       cancelToken: cancelToken,
     );
   }
@@ -903,7 +912,7 @@ class Channel {
 
   void _initState(ChannelState channelState) {
     state = ChannelClientState(this, channelState);
-    client.state.channels![cid] = this;
+    client.state.channels[cid!] = this;
     if (!_initializedCompleter.isCompleted) {
       _initializedCompleter.complete(true);
     }
@@ -1018,9 +1027,7 @@ class Channel {
     bool preferOffline = false,
   }) async {
     var path = '/channels/$type';
-    if (id != null) {
+    if (id != null) path = '$path/$id';
-      path = '$path/$id';
-    }
     path = '$path/query';
 
     final payload = Map<String, dynamic>.from({
@@ -1082,7 +1089,7 @@ class Channel {
 
   /// Query channel members
   Future<QueryMembersResponse> queryMembers({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption>? sort,
     PaginationParams? pagination,
   }) async {

packages/stream_chat/lib/src/client.dart

@@ -29,6 +29,8 @@ import 'package:stream_chat/src/platform_detector/platform_detector.dart';
 import 'package:stream_chat/version.dart';
 import 'package:uuid/uuid.dart';
 
+import 'package:stream_chat/src/models/filter.dart';
+
 /// Handler function used for logging records. Function requires a single
 /// [LogRecord] as the only parameter.
 typedef LogHandlerFunction = void Function(LogRecord record);
@@ -552,13 +554,11 @@ class StreamChatClient {
           type: EventType.connectionRecovered,
           online: true,
         ));
-        if (state.channels?.isNotEmpty == true) {
+        if (state.channels.isNotEmpty == true) {
           // ignore: unawaited_futures
-          queryChannelsOnline(filter: {
+          queryChannelsOnline(
-            'cid': {
+            filter: Filter.in_('cid', state.channels.keys.toList()),
-              '\$in': state.channels!.keys.toList(),
+          ).then(
-            },
-          }).then(
             (_) async {
               await resync();
             },
@@ -641,7 +641,7 @@ class StreamChatClient {
 
   /// Requests channels with a given query.
   Stream<List<Channel>> queryChannels({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sort,
     Map<String, dynamic>? options,
     PaginationParams paginationParams = const PaginationParams(),
@@ -684,7 +684,7 @@ class StreamChatClient {
 
   /// Requests channels with a given query from the API.
   Future<List<Channel>> queryChannelsOnline({
-    required Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sort,
     Map<String, dynamic>? options,
     int? messageLimit,
@@ -764,7 +764,7 @@ class StreamChatClient {
     final updateData = _mapChannelStateToChannel(channels);
 
     await _chatPersistenceClient?.updateChannelQueries(
-      filter ?? {},
+      filter,
       channels.map((c) => c.channel!.cid).toList(),
       clearQueryCache: paginationParams.offset == 0,
     );
@@ -775,8 +775,8 @@ class StreamChatClient {
 
   /// Requests channels with a given query from the Persistence client.
   Future<List<Channel>> queryChannelsOffline({
-    required Map<String, dynamic>? filter,
+    Filter? filter,
-    required List<SortOption<ChannelModel>>? sort,
+    List<SortOption<ChannelModel>>? sort,
     PaginationParams paginationParams = const PaginationParams(),
   }) async {
     final offlineChannels = (await _chatPersistenceClient?.getChannelStates(
@@ -790,10 +790,10 @@ class StreamChatClient {
     return updatedData.value;
   }
 
-  MapEntry<Map<String?, Channel>, List<Channel>> _mapChannelStateToChannel(
+  MapEntry<Map<String, Channel>, List<Channel>> _mapChannelStateToChannel(
     List<ChannelState> channelStates,
   ) {
-    final channels = {...state.channels ?? {}};
+    final channels = {...state.channels};
     final newChannels = <Channel>[];
     for (final channelState in channelStates) {
       final channel = channels[channelState.channel!.cid];
@@ -802,7 +802,7 @@ class StreamChatClient {
         newChannels.add(channel);
       } else {
         final newChannel = Channel.fromState(this, channelState);
-        channels[newChannel.cid] = newChannel;
+        channels[newChannel.cid!] = newChannel;
         newChannels.add(newChannel);
       }
     }
@@ -1020,7 +1020,7 @@ class StreamChatClient {
 
   /// Requests users with a given query.
   Future<QueryUsersResponse> queryUsers({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption>? sort,
     Map<String, dynamic>? options,
     PaginationParams? pagination,
@@ -1030,7 +1030,7 @@ class StreamChatClient {
     };
 
     final payload = <String, dynamic>{
-      'filter_conditions': filter ?? {},
+      'filter_conditions': filter,
       'sort': sort,
     }..addAll(defaultOptions);
 
@@ -1061,16 +1061,13 @@ class StreamChatClient {
 
   /// A message search.
   Future<SearchMessagesResponse> search(
-    Map<String, dynamic> filters, {
+    Filter filter, {
     String? query,
     List<SortOption>? sort,
     PaginationParams? paginationParams,
     Map<String, dynamic>? messageFilters,
   }) async {
     assert(() {
-      if (filters.isEmpty) {
-        throw ArgumentError('`filters` cannot be set as null or empty');
-      }
       if (query == null && messageFilters == null) {
         throw ArgumentError('Provide at least `query` or `messageFilters`');
       }
@@ -1083,7 +1080,7 @@ class StreamChatClient {
     }(), 'Check incoming params.');
 
     final payload = {
-      'filter_conditions': filters,
+      'filter_conditions': filter,
       'message_filter_conditions': messageFilters,
       'query': query,
       'sort': sort,
@@ -1194,15 +1191,12 @@ class StreamChatClient {
   Channel channel(
     String type, {
     String? id,
-    Map<String, dynamic> extraData = const {},
+    Map<String, Object> extraData = const {},
   }) {
-    if (id != null && state.channels?.containsKey('$type:$id') == true) {
+    if (id != null && state.channels.containsKey('$type:$id')) {
-      if (state.channels!['$type:$id'] != null) {
+      return state.channels['$type:$id']!;
-        return state.channels!['$type:$id'] as Channel;
-      }
     }
-
+    return Channel(this, type, id, extraData: extraData);
-    return Channel(this, type, id, extraData);
   }
 
   /// Update or Create the given user object.
@@ -1443,9 +1437,7 @@ class ClientState {
       if (cid != null) {
         _client.chatPersistenceClient?.deleteChannels([cid]);
       }
-      if (channels != null) {
+      channels = channels..removeWhere((cid, ch) => cid == event.cid);
-        channels = channels?..removeWhere((cid, ch) => cid == event.cid);
-      }
     }));
   }
 
@@ -1468,9 +1460,7 @@ class ClientState {
         .listen((Event event) async {
       final eventChannel = event.channel!;
       await _client.chatPersistenceClient?.deleteChannels([eventChannel.cid]);
-      if (channels != null) {
+      channels = channels..remove(eventChannel.cid);
-        channels = channels?..remove(eventChannel.cid);
-      }
     }));
   }
 
@@ -1521,13 +1511,13 @@ class ClientState {
       _channelsController.stream;
 
   /// The current list of channels in memory
-  Map<String?, Channel>? get channels => _channelsController.value;
+  Map<String, Channel> get channels => _channelsController.value!;
 
-  set channels(Map<String?, Channel>? v) {
+  set channels(Map<String, Channel>? v) {
-    _channelsController.add(v);
+    if (v != null) _channelsController.add(v);
   }
 
-  final BehaviorSubject<Map<String?, Channel>?> _channelsController =
+  final BehaviorSubject<Map<String, Channel>> _channelsController =
       BehaviorSubject.seeded({});
   final BehaviorSubject<OwnUser?> _userController = BehaviorSubject();
   final BehaviorSubject<Map<String?, User?>> _usersController =
@@ -1541,7 +1531,7 @@ class ClientState {
     _userController.close();
     _unreadChannelsController.close();
     _totalUnreadCountController.close();
-    channels!.values.forEach((c) => c.dispose());
+    channels.values.forEach((c) => c.dispose());
     _channelsController.close();
   }
 }

packages/stream_chat/lib/src/db/chat_persistence_client.dart

@@ -2,6 +2,7 @@ import 'package:stream_chat/src/api/requests.dart';
 import 'package:stream_chat/src/models/channel_model.dart';
 import 'package:stream_chat/src/models/channel_state.dart';
 import 'package:stream_chat/src/models/event.dart';
+import 'package:stream_chat/src/models/filter.dart';
 import 'package:stream_chat/src/models/member.dart';
 import 'package:stream_chat/src/models/message.dart';
 import 'package:stream_chat/src/models/reaction.dart';
@@ -90,7 +91,7 @@ abstract class ChatPersistenceClient {
   /// Optionally, pass [filter], [sort], [paginationParams]
   /// for filtering out states.
   Future<List<ChannelState>> getChannelStates({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sort,
     PaginationParams? paginationParams,
   });
@@ -100,7 +101,7 @@ abstract class ChatPersistenceClient {
   /// If [clearQueryCache] is true before the insert
   /// the list of matching rows will be deleted
   Future<void> updateChannelQueries(
-    Map<String, dynamic> filter,
+    Filter? filter,
     List<String> cids, {
     bool clearQueryCache = false,
   });

packages/stream_chat/lib/src/models/channel_model.dart

@@ -23,16 +23,16 @@ class ChannelModel {
     this.memberCount = 0,
     this.extraData,
     this.team,
-  })  : config = config ?? ChannelConfig(),
+  })  : assert(
-        createdAt = createdAt ?? DateTime.now(),
-        updatedAt = updatedAt ?? DateTime.now(),
-        assert(
           (cid != null && cid.contains(':')) || (id != null && type != null),
           'provide either a cid or an id and type',
         ),
         id = id ?? cid!.split(':')[1],
         type = type ?? cid!.split(':')[0],
-        cid = cid ?? '$type:$id';
+        cid = cid ?? '$type:$id',
+        config = config ?? ChannelConfig(),
+        createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now();
 
   /// Create a new instance from a json
   factory ChannelModel.fromJson(Map<String, dynamic> json) =>

packages/stream_chat/lib/src/models/filter.dart

@@ -0,0 +1,208 @@
+// ignore_for_file: non_constant_identifier_names, constant_identifier_names
+
+import 'package:equatable/equatable.dart';
+
+const _groupOperators = [
+  FilterOperator.and,
+  FilterOperator.or,
+  FilterOperator.nor,
+];
+
+/// Possible operators to use in filters.
+enum FilterOperator {
+  /// Matches values that are equal to a specified value.
+  equal,
+
+  /// Matches all values that are not equal to a specified value.
+  notEqual,
+
+  /// Matches values that are greater than a specified value.
+  greater,
+
+  /// Matches values that are greater than a specified value.
+  greaterOrEqual,
+
+  /// Matches values that are less than a specified value.
+  less,
+
+  /// Matches values that are less than or equal to a specified value.
+  lessOrEqual,
+
+  /// Matches any of the values specified in an array.
+  in_,
+
+  /// Matches none of the values specified in an array.
+  notIn,
+
+  /// Matches values by performing text search with the specified value.
+  query,
+
+  /// Matches values with the specified prefix.
+  autoComplete,
+
+  /// Matches values that exist/don't exist based on the specified boolean value.
+  exists,
+
+  /// Matches all the values specified in an array.
+  and,
+
+  /// Matches at least one of the values specified in an array.
+  or,
+
+  /// Matches none of the values specified in an array.
+  nor,
+}
+
+/// Helper extension for [FilterOperator]
+extension FilterOperatorX on FilterOperator {
+  /// Converts [FilterOperator] into rew values
+  String get rawValue => {
+        FilterOperator.equal: '\$eq',
+        FilterOperator.notEqual: '\$ne',
+        FilterOperator.greater: '\$gt',
+        FilterOperator.greaterOrEqual: '\$gte',
+        FilterOperator.less: '\$lt',
+        FilterOperator.lessOrEqual: '\$lte',
+        FilterOperator.in_: '\$in',
+        FilterOperator.notIn: '\$nin',
+        FilterOperator.query: '\$q',
+        FilterOperator.autoComplete: '\$autocomplete',
+        FilterOperator.exists: '\$exists',
+        FilterOperator.and: '\$and',
+        FilterOperator.or: '\$or',
+        FilterOperator.nor: '\$nor',
+      }[this]!;
+}
+
+/// Stream supports a limited set of filters for querying channels,
+/// users and members. The example below shows how to filter for channels
+/// of type messaging where the current user is a member
+///
+/// ```dart
+/// final filter = Filter.and(
+///     Filter.equal('type', 'messaging'),
+///     Filter.in_('members', [user.id])
+/// )
+/// ```
+/// See <a href="https://getstream.io/chat/docs/query_channels/?language=dart" target="_top">Query Channels Documentation</a>
+class Filter extends Equatable {
+  const Filter.__({
+    required this.operator,
+    required this.value,
+    this.key,
+  });
+
+  Filter._({
+    required FilterOperator operator,
+    required this.value,
+    this.key,
+  }) : operator = operator.rawValue;
+
+  /// Combines the provided filters and matches the values
+  /// matched by all filters.
+  factory Filter.and(List<Filter> filters) =>
+      Filter._(operator: FilterOperator.and, value: filters);
+
+  /// Combines the provided filters and matches the values
+  /// matched by at least one of the filters.
+  factory Filter.or(List<Filter> filters) =>
+      Filter._(operator: FilterOperator.or, value: filters);
+
+  /// Combines the provided filters and matches the values
+  /// not matched by all the filters.
+  factory Filter.nor(List<Filter> filters) =>
+      Filter._(operator: FilterOperator.nor, value: filters);
+
+  /// Matches values that are equal to a specified value.
+  factory Filter.equal(String key, Object value) =>
+      Filter._(operator: FilterOperator.equal, key: key, value: value);
+
+  /// Matches all values that are not equal to a specified value.
+  factory Filter.notEqual(String key, Object value) =>
+      Filter._(operator: FilterOperator.notEqual, key: key, value: value);
+
+  /// Matches values that are greater than a specified value.
+  factory Filter.greater(String key, Object value) =>
+      Filter._(operator: FilterOperator.greater, key: key, value: value);
+
+  /// Matches values that are greater than a specified value.
+  factory Filter.greaterOrEqual(String key, Object value) =>
+      Filter._(operator: FilterOperator.greaterOrEqual, key: key, value: value);
+
+  /// Matches values that are less than a specified value.
+  factory Filter.less(String key, Object value) =>
+      Filter._(operator: FilterOperator.less, key: key, value: value);
+
+  /// Matches values that are less than or equal to a specified value.
+  factory Filter.lessOrEqual(String key, Object value) =>
+      Filter._(operator: FilterOperator.lessOrEqual, key: key, value: value);
+
+  /// Matches any of the values specified in an array.
+  factory Filter.in_(String key, List<Object> values) =>
+      Filter._(operator: FilterOperator.in_, key: key, value: values);
+
+  /// Matches none of the values specified in an array.
+  factory Filter.notIn(String key, List<Object> values) =>
+      Filter._(operator: FilterOperator.notIn, key: key, value: values);
+
+  /// Matches values by performing text search with the specified value.
+  factory Filter.query(String key, String text) =>
+      Filter._(operator: FilterOperator.query, key: key, value: text);
+
+  /// Matches values with the specified prefix.
+  factory Filter.autoComplete(String key, String text) =>
+      Filter._(operator: FilterOperator.autoComplete, key: key, value: text);
+
+  /// Matches values that exist/don't exist based on the specified boolean value.
+  factory Filter.exists(String key, {bool exists = true}) =>
+      Filter._(operator: FilterOperator.exists, key: key, value: exists);
+
+  /// Creates a custom [Filter] if there isn't one already available.
+  const factory Filter.custom({
+    required String operator,
+    required Object value,
+    String? key,
+  }) = Filter.__;
+
+  /// An operator used for the filter. The operator string must start with `$`
+  final String operator;
+
+  /// The "left-hand" side of the filter.
+  /// Specifies the name of the field the filter should match.
+  ///
+  /// Some operators like `and` or `or`,
+  /// don't require the key value to be present.
+  /// see-more : [_groupOperators]
+  final String? key;
+
+  /// The "right-hand" side of the filter.
+  /// Specifies the [value] the filter should match.
+  final Object /*List<Object>|List<Filter>|String*/ value;
+
+  @override
+  List<Object?> get props => [operator, key, value];
+
+  /// Serializes to json object
+  Map<String, Object> toJson() {
+    final json = <String, Object>{};
+    final groupOperators = _groupOperators.map((it) => it.rawValue);
+
+    assert(
+      groupOperators.contains(operator) || key != null,
+      'Filter must contain the `key` when the operator is not a '
+      'group operator.',
+    );
+
+    if (groupOperators.contains(operator)) {
+      // Filters with group operators are encoded in the following form:
+      // { $<operator>: [ <filter 1>, <filter 2> ] }
+      json[operator] = value;
+    } else {
+      // Normal filters are encoded in the following form:
+      // { key: { $<operator>: <value> } }
+      json[key!] = {operator: value};
+    }
+
+    return json;
+  }
+}

packages/stream_chat/lib/stream_chat.dart

@@ -28,6 +28,7 @@ export './src/models/channel_state.dart';
 export './src/models/command.dart';
 export './src/models/device.dart';
 export './src/models/event.dart';
+export './src/models/filter.dart' show Filter;
 export './src/models/member.dart';
 export './src/models/message.dart';
 export './src/models/mute.dart';

packages/stream_chat/test/src/api/channel_test.dart

@@ -516,7 +516,7 @@ void main() {
       );
       await channelClient.watch();
 
-      final event = const Event(type: EventType.any);
+      const event = Event(type: EventType.any);
 
       when(
         () => mockDio.post<String>(
@@ -564,7 +564,7 @@ void main() {
       );
       await channelClient.watch();
 
-      final event = const Event(type: EventType.typingStart);
+      const event = Event(type: EventType.typingStart);
 
       when(
         () => mockDio.post<String>(
@@ -610,7 +610,7 @@ void main() {
       );
       await channelClient.watch();
 
-      final event = const Event(type: EventType.typingStop);
+      const event = Event(type: EventType.typingStop);
 
       when(
         () => mockDio.post<String>(

packages/stream_chat/test/src/client_test.dart

@@ -10,6 +10,7 @@ import 'package:stream_chat/src/api/requests.dart';
 import 'package:stream_chat/src/client.dart';
 import 'package:stream_chat/src/exceptions.dart';
 import 'package:stream_chat/src/models/channel_model.dart';
+import 'package:stream_chat/src/models/filter.dart';
 import 'package:stream_chat/src/models/message.dart';
 import 'package:stream_chat/src/models/user.dart';
 import 'package:test/test.dart';
@@ -89,7 +90,7 @@ void main() {
 
       test('Channel', () {
         final client = StreamChatClient('test');
-        final data = <String, dynamic>{'test': 1};
+        final data = <String, Object>{'test': 1};
         final channelClient = client.channel('type', id: 'id', extraData: data);
         expect(channelClient.type, 'type');
         expect(channelClient.id, 'id');
@@ -126,7 +127,7 @@ void main() {
           ),
         );
 
-        await client.queryChannelsOnline(filter: null, waitForConnect: false);
+        await client.queryChannelsOnline(waitForConnect: false);
 
         verify(() =>
                 mockDio.get<String>('/channels', queryParameters: queryParams))
@@ -140,11 +141,7 @@ void main() {
         when(() => mockDio.interceptors).thenReturn(Interceptors());
 
         final client = StreamChatClient('api-key', httpClient: mockDio);
-        final queryFilter = <String, dynamic>{
+        final queryFilter = Filter.in_('id', const ['test']);
-          'id': {
-            '\$in': ['test'],
-          },
-        };
         final sortOptions = <SortOption<ChannelModel>>[];
         final options = {'state': false, 'watch': false, 'presence': true};
         const paginationParams = PaginationParams(offset: 2);
@@ -192,11 +189,7 @@ void main() {
         when(() => mockDio.interceptors).thenReturn(Interceptors());
 
         final client = StreamChatClient('api-key', httpClient: mockDio);
-        final filter = {
+        final filter = Filter.in_('cid', const ['messaging:testId']);
-          'cid': {
-            r'$in': ['messaging:testId']
-          }
-        };
         const query = 'hello';
         final queryParams = {
           'payload': json.encode({
@@ -229,11 +222,7 @@ void main() {
         when(() => mockDio.interceptors).thenReturn(Interceptors());
 
         final client = StreamChatClient('api-key', httpClient: mockDio);
-        final filters = {
+        final filters = Filter.in_('id', const ['test']);
-          'id': {
-            '\$in': ['test'],
-          },
-        };
         const sortOptions = [SortOption('name')];
         const query = 'query';
         final queryParams = {
@@ -374,7 +363,7 @@ void main() {
         final client = StreamChatClient('api-key', httpClient: mockDio);
         final queryParams = {
           'payload': json.encode({
-            'filter_conditions': {},
+            'filter_conditions': null,
             'sort': null,
             'presence': false,
           }),
@@ -407,11 +396,7 @@ void main() {
         when(() => mockDio.interceptors).thenReturn(Interceptors());
 
         final client = StreamChatClient('api-key', httpClient: mockDio);
-        final queryFilter = <String, dynamic>{
+        final queryFilter = Filter.in_('id', const ['test']);
-          'id': {
-            '\$in': ['test'],
-          },
-        };
         const sortOptions = <SortOption>[];
         final options = {'presence': true};
         final queryParams = <String, dynamic>{
@@ -1163,8 +1148,11 @@ void main() {
           httpClient: mockDio,
         );
 
-        final channelClient =
+        final channelClient = client.channel(
-            client.channel('type', id: 'id', extraData: {'name': 'init'});
+          'type',
+          id: 'id',
+          extraData: {'name': 'init'},
+        );
 
         const update = {
           'set': {'name': 'demo'}

packages/stream_chat/test/src/models/filter_test.dart

@@ -0,0 +1,212 @@
+import 'dart:convert';
+
+import 'package:test/test.dart';
+import 'package:stream_chat/src/models/filter.dart';
+
+void main() {
+  group('operators', () {
+    test('equal', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.equal(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.equal.rawValue);
+    });
+
+    test('notEqual', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.notEqual(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.notEqual.rawValue);
+    });
+
+    test('greater', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.greater(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.greater.rawValue);
+    });
+
+    test('greaterOrEqual', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.greaterOrEqual(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.greaterOrEqual.rawValue);
+    });
+
+    test('less', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.less(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.less.rawValue);
+    });
+
+    test('lessOrEqual', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      final filter = Filter.lessOrEqual(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.lessOrEqual.rawValue);
+    });
+
+    test('in', () {
+      const key = 'testKey';
+      const values = ['testValue'];
+      final filter = Filter.in_(key, values);
+      expect(filter.key, key);
+      expect(filter.value, values);
+      expect(filter.operator, FilterOperator.in_.rawValue);
+    });
+
+    test('in', () {
+      const key = 'testKey';
+      const values = ['testValue'];
+      final filter = Filter.in_(key, values);
+      expect(filter.key, key);
+      expect(filter.value, values);
+      expect(filter.operator, FilterOperator.in_.rawValue);
+    });
+
+    test('notIn', () {
+      const key = 'testKey';
+      const values = ['testValue'];
+      final filter = Filter.notIn(key, values);
+      expect(filter.key, key);
+      expect(filter.value, values);
+      expect(filter.operator, FilterOperator.notIn.rawValue);
+    });
+
+    test('query', () {
+      const key = 'testKey';
+      const value = 'testQuery';
+      final filter = Filter.query(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.query.rawValue);
+    });
+
+    test('autoComplete', () {
+      const key = 'testKey';
+      const value = 'testQuery';
+      final filter = Filter.autoComplete(key, value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, FilterOperator.autoComplete.rawValue);
+    });
+
+    test('exists', () {
+      const key = 'testKey';
+      final filter = Filter.exists(key);
+      expect(filter.key, key);
+      expect(filter.value, isTrue);
+      expect(filter.operator, FilterOperator.exists.rawValue);
+    });
+
+    test('notExists', () {
+      const key = 'testKey';
+      final filter = Filter.exists(key, exists: false);
+      expect(filter.key, key);
+      expect(filter.value, isFalse);
+      expect(filter.operator, FilterOperator.exists.rawValue);
+    });
+
+    test('custom', () {
+      const key = 'testKey';
+      const value = 'testValue';
+      const operator = '\$customOperator';
+      const filter = Filter.custom(operator: operator, key: key, value: value);
+      expect(filter.key, key);
+      expect(filter.value, value);
+      expect(filter.operator, operator);
+    });
+
+    group('groupedOperator', () {
+      final filter1 = Filter.equal('testKey', 'testValue');
+      final filter2 = Filter.in_('testKey', const ['testValue']);
+      final filters = [filter1, filter2];
+
+      test('and', () {
+        final filter = Filter.and(filters);
+        expect(filter.key, isNull);
+        expect(filter.value, filters);
+        expect(filter.operator, FilterOperator.and.rawValue);
+      });
+
+      test('or', () {
+        final filter = Filter.or(filters);
+        expect(filter.key, isNull);
+        expect(filter.value, filters);
+        expect(filter.operator, FilterOperator.or.rawValue);
+      });
+
+      test('nor', () {
+        final filter = Filter.nor(filters);
+        expect(filter.key, isNull);
+        expect(filter.value, filters);
+        expect(filter.operator, FilterOperator.nor.rawValue);
+      });
+    });
+  });
+
+  group('encoding', () {
+    group('nonGroupedFilter', () {
+      test('simpleValue', () {
+        const key = 'testKey';
+        const value = 'testValue';
+        final filter = Filter.equal(key, value);
+        final encoded = json.encode(filter);
+        expect(
+          encoded,
+          '{"$key":{"${FilterOperator.equal.rawValue}":${json.encode(value)}}}',
+        );
+      });
+      test('listValue', () {
+        const key = 'testKey';
+        const values = ['testValue'];
+        final filter = Filter.in_(key, values);
+        final encoded = json.encode(filter);
+        expect(
+          encoded,
+          '{"$key":{"${FilterOperator.in_.rawValue}":${json.encode(values)}}}',
+        );
+      });
+    });
+
+    test('groupedFilter', () {
+      final filter1 = Filter.equal('testKey', 'testValue');
+      final filter2 = Filter.in_('testKey', const ['testValue']);
+      final filters = [filter1, filter2];
+
+      final filter = Filter.and(filters);
+      final encoded = json.encode(filter);
+      expect(
+        encoded,
+        '{"${FilterOperator.and.rawValue}":${json.encode(filters)}}',
+      );
+    });
+
+    group('equality', () {
+      test('simpleFilter', () {
+        final filter1 = Filter.equal('testKey', 'testValue');
+        final filter2 = Filter.equal('testKey', 'testValue');
+        expect(filter1, filter2);
+      });
+
+      test('groupedFilter', () {
+        final filter1 = Filter.and([Filter.equal('testKey', 'testValue')]);
+        final filter2 = Filter.and([Filter.equal('testKey', 'testValue')]);
+        expect(filter1, filter2);
+      });
+    });
+  });
+}

packages/stream_chat_flutter/example/lib/split_view.dart

@@ -93,11 +93,10 @@ class ChannelListPage extends StatelessWidget {
                   onTap(channel);
                 }
               : null,
-          filter: {
+          filter: Filter.in_(
-            'members': {
+            'members',
-              '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            }
+          ),
-          },
           sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,

packages/stream_chat_flutter/example/lib/tutorial-part-2.dart

@@ -56,11 +56,10 @@ class ChannelListPage extends StatelessWidget {
     return Scaffold(
       body: ChannelsBloc(
         child: ChannelListView(
-          filter: {
+          filter: Filter.in_(
-            // 'members': {
+            'members',
-            //   '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            // }
+          ),
-          },
           sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,

packages/stream_chat_flutter/example/lib/tutorial-part-3.dart

@@ -57,11 +57,10 @@ class ChannelListPage extends StatelessWidget {
     return Scaffold(
       body: ChannelsBloc(
         child: ChannelListView(
-          filter: {
+          filter: Filter.in_(
-            'members': {
+            'members',
-              '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            }
+          ),
-          },
           channelPreviewBuilder: _channelPreviewBuilder,
           // sort: [SortOption('last_message_at')],
           pagination: PaginationParams(

packages/stream_chat_flutter/example/lib/tutorial-part-4.dart

@@ -49,11 +49,10 @@ class ChannelListPage extends StatelessWidget {
     return Scaffold(
       body: ChannelsBloc(
         child: ChannelListView(
-          filter: {
+          filter: Filter.in_(
-            'members': {
+            'members',
-              '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            }
+          ),
-          },
           sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,

packages/stream_chat_flutter/example/lib/tutorial-part-5.dart

@@ -52,11 +52,10 @@ class ChannelListPage extends StatelessWidget {
     return Scaffold(
       body: ChannelsBloc(
         child: ChannelListView(
-          filter: {
+          filter: Filter.in_(
-            'members': {
+            'members',
-              '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            }
+          ),
-          },
           sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,

packages/stream_chat_flutter/example/lib/tutorial-part-6.dart

@@ -80,11 +80,10 @@ class ChannelListPage extends StatelessWidget {
     return Scaffold(
       body: ChannelsBloc(
         child: ChannelListView(
-          filter: {
+          filter: Filter.in_(
-            'members': {
+            'members',
-              '\$in': [StreamChat.of(context).user.id],
+            [StreamChat.of(context).user.id],
-            }
+          ),
-          },
           sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,

packages/stream_chat_flutter/lib/src/channel_list_view.dart

@@ -84,7 +84,7 @@ class ChannelListView extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic> filter;
+  final Filter filter;
 
   /// Query channels options.
   ///

packages/stream_chat_flutter/lib/src/message_input.dart

@@ -1243,11 +1243,10 @@ class MessageInputState extends State<MessageInput> {
     Future<List<Member>> queryMembers;
 
     if (query.isNotEmpty) {
-      queryMembers = StreamChannel.of(context).channel.queryMembers(filter: {
+      queryMembers = StreamChannel.of(context)
-        'name': {
+          .channel
-          '\$autocomplete': query,
+          .queryMembers(filter: Filter.autoComplete('name', query))
-        },
+          .then((res) => res.members);
-      }).then((res) => res.members);
     }
 
     final members = StreamChannel.of(context).channel.state.members?.where((m) {
@@ -2096,7 +2095,7 @@ class MessageInputState extends State<MessageInput> {
     }
 
     return sendingFuture.then((resp) {
-      if (resp.message?.type == 'error') {
+      if (resp.message?._type == 'error') {
         _parseExistingMessage(message);
       }
       if (widget.onMessageSent != null) {

packages/stream_chat_flutter/lib/src/message_search_list_view.dart

@@ -71,7 +71,7 @@ class MessageSearchListView extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic> filters;
+  final Filter filters;
 
   /// The sorting used for the channels matching the filters.
   /// Sorting is based on field and direction, multiple sorting options can be provided.

packages/stream_chat_flutter/lib/src/user_list_view.dart

@@ -72,7 +72,7 @@ class UserListView extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic> filter;
+  final Filter filter;
 
   /// Query channels options.
   ///

packages/stream_chat_flutter_core/analysis_options.yaml

@@ -4,6 +4,7 @@ analyzer:
     - lib/**/*.freezed.dart
     - example/*
     - test/*
+
 linter:
   rules:
     - always_use_package_imports

packages/stream_chat_flutter_core/example/lib/main.dart

@@ -78,14 +78,12 @@ class HomeScreen extends StatelessWidget {
       body: ChannelsBloc(
         child: ChannelListCore(
           channelListController: channelListController,
-          filter: {
+          filter: Filter.and([
-            'type': 'messaging',
+            Filter.equal('type', 'messaging'),
-            'members': {
+            Filter.in_('members', [
-              r'$in': [
+              StreamChatCore.of(context).user!.id,
-                StreamChatCore.of(context).user!.id,
+            ])
-              ]
+          ]),
-            }
-          },
           emptyBuilder: (BuildContext context) {
             return Center(
               child: Text('Looks like you are not in any channels'),

packages/stream_chat_flutter_core/lib/src/channel_list_core.dart

@@ -92,7 +92,7 @@ class ChannelListCore extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic>? filter;
+  final Filter? filter;
 
   /// Query channels options.
   ///

packages/stream_chat_flutter_core/lib/src/channels_bloc.dart

@@ -88,7 +88,7 @@ class ChannelsBlocState extends State<ChannelsBloc>
 
   /// Calls [client.queryChannels] updating [queryChannelsLoading] stream
   Future<void> queryChannels({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sortOptions,
     PaginationParams paginationParams = const PaginationParams(limit: 30),
     Map<String, dynamic>? options,
@@ -160,9 +160,8 @@ class ChannelsBlocState extends State<ChannelsBloc>
             newChannels.insert(0, _hiddenChannels[hiddenIndex]);
             _hiddenChannels.removeAt(hiddenIndex);
           } else {
-            if (client.state.channels != null &&
+            if (client.state.channels[e.cid] != null) {
-                client.state.channels?[e.cid] != null) {
+              newChannels.insert(0, client.state.channels[e.cid]!);
-              newChannels.insert(0, client.state.channels![e.cid]!);
             }
           }
         }

packages/stream_chat_flutter_core/lib/src/message_search_bloc.dart

@@ -9,7 +9,7 @@ import 'package:stream_chat_flutter_core/src/stream_chat_core.dart';
 /// [MessageSearchBloc] can be access at anytime by using the static [of] method
 /// using Flutter's [BuildContext].
 ///
-// API docs: https://getstream.io/chat/docs/flutter-dart/send_message/
+/// API docs: https://getstream.io/chat/docs/flutter-dart/send_message/
 class MessageSearchBloc extends StatefulWidget {
   /// Instantiate a new MessageSearchBloc
   const MessageSearchBloc({
@@ -58,7 +58,7 @@ class MessageSearchBlocState extends State<MessageSearchBloc>
   /// Calls [StreamChatClient.search] updating
   /// [messagesStream] and [queryMessagesLoading] stream
   Future<void> search({
-    required Map<String, dynamic> filter,
+    required Filter filter,
     Map<String, dynamic>? messageFilter,
     List<SortOption>? sort,
     String? query,

packages/stream_chat_flutter_core/lib/src/message_search_list_core.dart

@@ -67,7 +67,7 @@ class MessageSearchListCore extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic> filters;
+  final Filter filters;
 
   /// The sorting used for the channels matching the filters.
   /// Sorting is based on field and direction, multiple sorting options can be

packages/stream_chat_flutter_core/lib/src/user_list_core.dart

@@ -90,7 +90,7 @@ class UserListCore extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic>? filter;
+  final Filter? filter;
 
   /// Query channels options.
   ///

packages/stream_chat_flutter_core/lib/src/users_bloc.dart

@@ -58,7 +58,7 @@ class UsersBlocState extends State<UsersBloc>
   /// online/offline.
   /// [API Reference](https://getstream.io/chat/docs/flutter-dart/query_users/?language=dart)
   Future<void> queryUsers({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption>? sort,
     Map<String, dynamic>? options,
     PaginationParams? pagination,

packages/stream_chat_flutter_core/test/channel_list_core_test.dart

@@ -24,7 +24,7 @@ void main() {
           client,
           'testType$index',
           'testId$index',
-          {'extra_data_key': 'extra_data_value_$index'},
+          extraData: {'extra_data_key': 'extra_data_value_$index'},
         );
       },
     );

packages/stream_chat_flutter_core/test/channels_bloc_test.dart

@@ -26,7 +26,7 @@ void main() {
           client,
           'testType$index',
           'testId$index',
-          {'extra_data_key': 'extra_data_value_$index'},
+          extraData: {'extra_data_key': 'extra_data_value_$index'},
         );
       },
     );
@@ -703,7 +703,7 @@ void main() {
         final mockClient = MockClient();
         final channels = _generateChannels(mockClient);
         final stateChannels = {
-          for (var c in _generateChannels(mockClient, offset: 5)) c.cid: c
+          for (var c in _generateChannels(mockClient, offset: 5)) c.cid!: c
         };
         const channelsBlocKey = Key('channelsBloc');
         final channelsBloc = ChannelsBloc(

packages/stream_chat_flutter_core/test/message_search_bloc_test.dart

@@ -8,6 +8,8 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'matchers/get_message_response_matcher.dart';
 import 'mocks.dart';
 
+final testFilter = Filter.custom(operator: '\$test', value: 'testValue');
+
 void main() {
   List<GetMessageResponse> _generateMessages({
     int count = 3,
@@ -50,7 +52,7 @@ void main() {
       );
 
       try {
-        await usersBlocState.search(filter: {});
+        await usersBlocState.search(filter: testFilter);
       } catch (e) {
         expect(e, isInstanceOf<Exception>());
       }
@@ -82,7 +84,7 @@ void main() {
       final messageResponseList = _generateMessages();
 
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -91,7 +93,7 @@ void main() {
         (_) async => SearchMessagesResponse()..results = messageResponseList,
       );
 
-      messageSearchBlocState.search(filter: {});
+      messageSearchBlocState.search(filter: testFilter);
 
       await expectLater(
         messageSearchBlocState.messagesStream,
@@ -99,7 +101,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -133,14 +135,14 @@ void main() {
 
       const error = 'Error! Error! Error!';
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
             paginationParams: any(named: 'paginationParams'),
           )).thenThrow(error);
 
-      messageSearchBlocState.search(filter: {});
+      messageSearchBlocState.search(filter: testFilter);
 
       await expectLater(
         messageSearchBlocState.messagesStream,
@@ -148,7 +150,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -185,7 +187,7 @@ void main() {
       final messageResponseList = _generateMessages();
 
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -194,7 +196,7 @@ void main() {
         (_) async => SearchMessagesResponse()..results = messageResponseList,
       );
 
-      messageSearchBlocState.search(filter: {});
+      messageSearchBlocState.search(filter: testFilter);
 
       await expectLater(
         messageSearchBlocState.messagesStream,
@@ -202,7 +204,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -214,7 +216,7 @@ void main() {
       final pagination = PaginationParams(offset: offset);
 
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -224,7 +226,7 @@ void main() {
             SearchMessagesResponse()..results = paginatedMessageResponseList,
       );
 
-      messageSearchBlocState.search(pagination: pagination, filter: {});
+      messageSearchBlocState.search(pagination: pagination, filter: testFilter);
 
       await Future.wait([
         expectLater(
@@ -240,7 +242,7 @@ void main() {
       ]);
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -277,7 +279,7 @@ void main() {
       final messageResponseList = _generateMessages();
 
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -286,7 +288,7 @@ void main() {
         (_) async => SearchMessagesResponse()..results = messageResponseList,
       );
 
-      messageSearchBlocState.search(filter: {});
+      messageSearchBlocState.search(filter: testFilter);
 
       await expectLater(
         messageSearchBlocState.messagesStream,
@@ -294,7 +296,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -306,14 +308,14 @@ void main() {
 
       const error = 'Error! Error! Error!';
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
             paginationParams: pagination,
           )).thenThrow(error);
 
-      messageSearchBlocState.search(pagination: pagination, filter: {});
+      messageSearchBlocState.search(pagination: pagination, filter: testFilter);
 
       await expectLater(
         messageSearchBlocState.queryMessagesLoading,
@@ -321,7 +323,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),

packages/stream_chat_flutter_core/test/message_search_list_core_test.dart

@@ -6,6 +6,8 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 import 'mocks.dart';
 
+final testFilter = Filter.custom(operator: '\$test', value: 'testValue');
+
 void main() {
   List<GetMessageResponse> _generateMessages({
     int count = 3,
@@ -37,7 +39,7 @@ void main() {
         loadingBuilder: (BuildContext context) => const Offstage(),
         emptyBuilder: (BuildContext context) => const Offstage(),
         errorBuilder: (BuildContext context, Object? error) => const Offstage(),
-        filters: const {},
+        filters: testFilter,
       );
 
       await tester.pumpWidget(messageSearchListCore);
@@ -58,7 +60,7 @@ void main() {
         loadingBuilder: (BuildContext context) => Offstage(),
         emptyBuilder: (BuildContext context) => Offstage(),
         errorBuilder: (BuildContext context, Object? error) => Offstage(),
-        filters: {},
+        filters: testFilter,
       );
 
       final mockClient = MockClient();
@@ -89,7 +91,7 @@ void main() {
         emptyBuilder: (BuildContext context) => Offstage(),
         errorBuilder: (BuildContext context, Object error) => Offstage(),
         messageSearchListController: controller,
-        filters: {},
+        filters: testFilter,
       );
 
       expect(controller.loadData, isNull);
@@ -125,14 +127,14 @@ void main() {
         errorBuilder: (BuildContext context, Object error) => Offstage(
           key: errorWidgetKey,
         ),
-        filters: {},
+        filters: testFilter,
       );
 
       final mockClient = MockClient();
 
       const error = 'Error! Error! Error!';
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -153,7 +155,7 @@ void main() {
       expect(find.byKey(errorWidgetKey), findsOneWidget);
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -174,14 +176,14 @@ void main() {
         loadingBuilder: (BuildContext context) => Offstage(),
         emptyBuilder: (BuildContext context) => Offstage(key: emptyWidgetKey),
         errorBuilder: (BuildContext context, Object error) => Offstage(),
-        filters: {},
+        filters: testFilter,
       );
 
       final mockClient = MockClient();
 
       final messageResponseList = <GetMessageResponse>[];
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -204,7 +206,7 @@ void main() {
       expect(find.byKey(emptyWidgetKey), findsOneWidget);
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -226,14 +228,14 @@ void main() {
         loadingBuilder: (BuildContext context) => Offstage(),
         emptyBuilder: (BuildContext context) => Offstage(),
         errorBuilder: (BuildContext context, Object error) => Offstage(),
-        filters: {},
+        filters: testFilter,
       );
 
       final mockClient = MockClient();
 
       final messageResponseList = _generateMessages();
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -256,7 +258,7 @@ void main() {
       expect(find.byKey(childWidgetKey), findsOneWidget);
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -284,14 +286,14 @@ void main() {
         emptyBuilder: (BuildContext context) => Offstage(),
         errorBuilder: (BuildContext context, Object error) => Offstage(),
         paginationParams: pagination,
-        filters: {},
+        filters: testFilter,
       );
 
       final mockClient = MockClient();
 
       final messageResponseList = _generateMessages();
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -325,7 +327,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -341,7 +343,7 @@ void main() {
       final paginatedMessageResponseList = _generateMessages(offset: offset);
       final updatedPagination = pagination.copyWith(offset: offset);
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -365,7 +367,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -400,14 +402,14 @@ void main() {
             emptyBuilder: (BuildContext context) => Offstage(),
             errorBuilder: (BuildContext context, Object error) => Offstage(),
             paginationParams: pagination.copyWith(limit: limit),
-            filters: {},
+            filters: testFilter,
           );
 
       final mockClient = MockClient();
 
       final messageResponseList = _generateMessages();
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -445,7 +447,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -458,7 +460,7 @@ void main() {
       final updatedMessageResponseList = _generateMessages(count: limit);
       final updatedPagination = pagination.copyWith(limit: limit);
       when(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),
@@ -479,7 +481,7 @@ void main() {
       );
 
       verify(() => mockClient.search(
-            any(),
+            testFilter,
             query: any(named: 'query'),
             sort: any(named: 'sort'),
             messageFilters: any(named: 'messageFilters'),

packages/stream_chat_persistence/lib/src/dao/channel_query_dao.dart

@@ -18,7 +18,7 @@ class ChannelQueryDao extends DatabaseAccessor<MoorChatDatabase>
   /// Creates a new channel query dao instance
   ChannelQueryDao(MoorChatDatabase db) : super(db);
 
-  String _computeHash(Map<String, dynamic>? filter) {
+  String _computeHash(Filter? filter) {
     if (filter == null) {
       return 'allchannels';
     }
@@ -30,7 +30,7 @@ class ChannelQueryDao extends DatabaseAccessor<MoorChatDatabase>
   /// If [clearQueryCache] is true before the insert
   /// the list of matching rows will be deleted
   Future<void> updateChannelQueries(
-    Map<String, dynamic> filter,
+    Filter? filter,
     List<String> cids, {
     bool clearQueryCache = false,
   }) async =>
@@ -58,7 +58,7 @@ class ChannelQueryDao extends DatabaseAccessor<MoorChatDatabase>
       });
 
   ///
-  Future<List<String>> getCachedChannelCids(Map<String, dynamic>? filter) {
+  Future<List<String>> getCachedChannelCids(Filter? filter) {
     final hash = _computeHash(filter);
     return (select(channelQueries)..where((c) => c.queryHash.equals(hash)))
         .map((c) => c.channelCid)
@@ -67,7 +67,7 @@ class ChannelQueryDao extends DatabaseAccessor<MoorChatDatabase>
 
   /// Get list of channels by filter, sort and paginationParams
   Future<List<ChannelModel>> getChannels({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sort,
     PaginationParams? paginationParams,
   }) async {

packages/stream_chat_persistence/lib/src/stream_chat_persistence_client.dart

@@ -253,7 +253,7 @@ class StreamChatPersistenceClient extends ChatPersistenceClient {
 
   @override
   Future<List<ChannelState>> getChannelStates({
-    Map<String, dynamic>? filter,
+    Filter? filter,
     List<SortOption<ChannelModel>>? sort,
     PaginationParams? paginationParams,
   }) {
@@ -273,7 +273,7 @@ class StreamChatPersistenceClient extends ChatPersistenceClient {
 
   @override
   Future<void> updateChannelQueries(
-    Map<String, dynamic> filter,
+    Filter? filter,
     List<String> cids, {
     bool clearQueryCache = false,
   }) {

packages/stream_chat_persistence/test/src/dao/channel_query_dao_test.dart

@@ -17,11 +17,7 @@ void main() {
   });
 
   test('updateChannelQueries', () async {
-    const filter = {
+    final filter = Filter.in_('members', const ['testUserId']);
-      'members': {
-        r'$in': ['testUserId'],
-      },
-    };
 
     const cids = ['testCid1', 'testCid2', 'testCid3'];
 
@@ -36,11 +32,7 @@ void main() {
   });
 
   test('clear queryCache before updateChannelQueries', () async {
-    const filter = {
+    final filter = Filter.in_('members', const ['testUserId']);
-      'members': {
-        r'$in': ['testUserId'],
-      },
-    };
 
     const cids = ['testCid1', 'testCid2', 'testCid3'];
 
@@ -59,11 +51,7 @@ void main() {
   });
 
   test('getCachedChannelCids', () async {
-    const filter = {
+    final filter = Filter.in_('members', const ['testUserId']);
-      'members': {
-        r'$in': ['testUserId'],
-      },
-    };
 
     const cids = ['testCid1', 'testCid2', 'testCid3'];
 
@@ -78,7 +66,7 @@ void main() {
   });
 
   Future<List<ChannelModel>> _insertTestDataForGetChannel(
-    Map<String, Object> filter, {
+    Filter filter, {
     int count = 3,
   }) async {
     final now = DateTime.now();
@@ -110,11 +98,7 @@ void main() {
   }
 
   group('getChannels', () {
-    const filter = {
+    final filter = Filter.in_('members', const ['testUserId']);
-      'members': {
-        r'$in': ['testUserId'],
-      },
-    };
 
     test('should return empty list of channels', () async {
       final channels = await channelQueryDao.getChannels(filter: filter);

packages/stream_chat_persistence/test/stream_chat_persistence_client_test.dart

@@ -292,7 +292,7 @@ void main() {
     });
 
     test('updateChannelQueries', () async {
-      const filter = <String, dynamic>{};
+      final filter = Filter.in_('members', const ['testUserId']);
       const cids = <String>[];
       when(() =>
               mockDatabase.channelQueryDao.updateChannelQueries(filter, cids))