fix: switchChildren not emitting any value when empty map

appsup-dart · Feb 26, 2024 · 5bcb261 · 5bcb261
1 parent 2b50b44
commit 5bcb261
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/lib/src/stream.dart b/lib/src/stream.dart
@@ -116,7 +116,7 @@ extension SnapshotStreamX on Stream<Snapshot> {
           Stream<dynamic> Function(String key, Snapshot value) mapper) =>
       switchMap((s) {
         var keys = s.asMap()?.keys;
-        if (keys == null) return Stream.value(s);
+        if (keys == null || keys.isEmpty) return Stream.value(s);
         return CombineLatestStream(
             keys.map((k) => mapper(k, s.child(k)).map((v) => MapEntry(k, v))),
             (List<MapEntry<String, dynamic>> l) {

diff --git a/test/stream_test.dart b/test/stream_test.dart
@@ -243,6 +243,15 @@ void main() async {
         expect((await stream.first).as(),
             {'jane': 'Jane Doe', 'john': 'John Doe'});
       });
+
+      test('with empty map', () async {
+        var stream = Stream<Snapshot>.value(Snapshot.fromJson({}));
+
+        stream = stream.switchChildren((key, value) => Stream.value(
+            '${value.child('firstname').as()} ${value.child('lastname').as()}'));
+
+        expect((await stream.first).as(), {});
+      });
     });
     group('Stream<Snapshot>.recycle', () {
       test('Stream<Snapshot>.recycle', () async {