Merge pull request #662 from GetStream/feat/filters

feat(llc): add `Filter.contains` and `Filter.empty`

docusaurus/docs/Flutter/guides/understanding_filters.mdx

@@ -107,6 +107,48 @@ The 'exists' filter matches values that exist, or don't exist, based on the spec
 Filter.exists('name', true)
 ```
 
+#### Filter.contains
+
+The 'contains' filter matches any list that contains the specified value.
+
+```dart
+Filter.contains('teams', 'red')
+```
+
+#### Filter.empty
+
+The 'empty' filter constructor returns an empty filter. It's the equivalent of an empty map `{}`;
+
+```dart
+Filter.empty();
+```
+
+#### Filter.raw
+
+The 'raw' filter constructor lets you specify a raw filter. We suggest using this only if you can't manage to build what you want using the other constructors.
+
+```dart
+Filter.raw(value: {
+  'members': [
+    ..._selectedUsers.map((e) => e.id),
+    chatState.currentUser!.id,
+  ],
+  'distinct': true,
+});
+```
+
+#### Filter.custom
+
+The 'custom' filter is used to create a custom filter in case it does not exists or it's not been added to the SDK yet.
+Note that the filter must be supported by the Stream backend in order to work.
+
+```dart
+Filter.custom(
+  operator: '\$max',
+  value: 10,
+)
+```
+
 ### Group Queries
 
 #### Filter.and

packages/stream_chat/CHANGELOG.md

@@ -10,6 +10,10 @@
     - `updatePinnedMessageReactions`
     - `deletePinnedMessageReactionsByMessageId`
 
+✅ Added
+
+- Added `Filter.contains` and `Filter.empty`
+
 ## 2.2.1
 
 🐞 Fixed

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

@@ -51,6 +51,9 @@ enum FilterOperator {
 
   /// Matches none of the values specified in an array.
   nor,
+
+  /// Matches any list that contains the specified value
+  contains,
 }
 
 /// Helper extension for [FilterOperator]
@@ -71,6 +74,7 @@ extension FilterOperatorX on FilterOperator {
         FilterOperator.and: '\$and',
         FilterOperator.or: '\$or',
         FilterOperator.nor: '\$nor',
+        FilterOperator.contains: '\$contains',
       }[this]!;
 }
 
@@ -157,6 +161,10 @@ class Filter extends Equatable {
   factory Filter.exists(String key, {bool exists = true}) =>
       Filter._(operator: FilterOperator.exists, key: key, value: exists);
 
+  /// Matches any list that contains the specified values
+  factory Filter.contains(String key, Object value) =>
+      Filter._(operator: FilterOperator.contains, key: key, value: value);
+
   /// Creates a custom [Filter] if there isn't one already available.
   const factory Filter.custom({
     required Object value,
@@ -164,6 +172,9 @@ class Filter extends Equatable {
     String? key,
   }) = Filter.__;
 
+  /// An empty filter
+  factory Filter.empty() => const Filter.raw(value: {});
+
   /// Creates a custom [Filter] from a raw map value
   ///
   /// ```dart

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

@@ -138,6 +138,20 @@ void main() {
       expect(filter.value, value);
     });
 
+    test('empty', () {
+      final filter = Filter.empty();
+      expect(filter.value, {});
+    });
+
+    test('contains', () {
+      const key = 'testKey';
+      const values = 'testValue';
+      final filter = Filter.contains(key, values);
+      expect(filter.key, key);
+      expect(filter.value, values);
+      expect(filter.operator, FilterOperator.contains.rawValue);
+    });
+
     group('groupedOperator', () {
       final filter1 = Filter.equal('testKey', 'testValue');
       final filter2 = Filter.in_('testKey', const ['testValue']);