feat: add streamJoin4

lib/stream/stream_join.dart

@@ -162,3 +162,24 @@ Stream<(StreamJoinItem<T1>, StreamJoinItem<T2>, StreamJoinItem<T3>)>
       (event) =>
           (event[0].cast<T1>(), event[1].cast<T2>(), event[2].cast<T3>()));
 }
+
+/// Join 4 streams
+Stream<(T1, T2, T3, T4)> streamJoin4<T1 extends Object?, T2 extends Object?,
+        T3 extends Object?, T4 extends Object?>(Stream<T1> stream1,
+    Stream<T2> stream2, Stream<T3> stream3, Stream<T4> stream4) {
+  return streamJoinAll<Object?>([stream1, stream2, stream3, stream4]).map(
+      (event) =>
+          (event[0] as T1, event[1] as T2, event[2] as T3, event[3] as T4));
+}
+
+/// Join 4 streams
+Stream<(T1, T2, T3, T4)> streamJoin4OrError<T1 extends Object?,
+        T2 extends Object?, T3 extends Object?, T4 extends Object?>(
+    Stream<T1> stream1,
+    Stream<T2> stream2,
+    Stream<T3> stream3,
+    Stream<T4> stream4) {
+  return streamJoinAllOrError<Object?>([stream1, stream2, stream3, stream4])
+      .map((event) =>
+          (event[0] as T1, event[1] as T2, event[2] as T3, event[3] as T4));
+}

pubspec.yaml

@@ -1,5 +1,5 @@
 name: tekartik_common_utils
-version: 0.15.11
+version: 0.15.12
 description: Common pure dart utilities (not io or browser dependant)
 homepage: https://github.com/tekartik/common_utils.dart
 publish_to: none

test/stream/stream_join_test.dart

@@ -42,6 +42,13 @@ void main() {
           .first;
       expect(value, equals((1, '2', null)));
     });
+    test('streamJoin4', () async {
+      (int?, String, String?, int?) value;
+      value = await streamJoin4(oneIntStream(), oneStringStream(),
+              anotherOptionalStringStream(null), oneIntStream(10))
+          .first;
+      expect(value, equals((1, '2', null, 10)));
+    });
     test('streamJoinAll', () {
       expect(emptyStream(), emitsInOrder([emitsDone]));
       expect(streamJoinAll([emptyStream()]), emitsInOrder([emitsDone]));