Small tweak (dart-lang/web_socket_channel#295)

pkgs/web_socket_channel/lib/html.dart

diff --git a/pkgs/web_socket_channel/lib/html.dart b/pkgs/web_socket_channel/lib/html.dart
index 2263e6e..6b3ea6e 100644
--- a/pkgs/web_socket_channel/lib/html.dart
+++ b/pkgs/web_socket_channel/lib/html.dart
@@ -78,10 +78,7 @@
       : this(
           WebSocket(
             url.toString(),
-            (protocols?.toList() ?? const <String>[])
-                .map((e) => e.toJS)
-                .toList()
-                .toJS,
+            protocols?.map((e) => e.toJS).toList().toJS ?? JSArray(),
           )..binaryType = (binaryType ?? BinaryType.list).value,
         );