fix: correctly detect WebSocket server

ilijaNL · Aug 26, 2020 · eab29dc · eab29dc
1 parent 2dcf72a
commit eab29dc
Showing 1 changed file with 7 additions and 4 deletions.
diff --git a/src/server.ts b/src/server.ts
@@ -198,10 +198,9 @@ export function createServer(
     onSubscribe,
     onComplete,
   } = options;
-  const webSocketServer =
-    websocketOptionsOrServer instanceof WebSocket.Server
-      ? websocketOptionsOrServer
-      : new WebSocket.Server(websocketOptionsOrServer);
+  const webSocketServer = isWebSocketServer(websocketOptionsOrServer)
+    ? websocketOptionsOrServer
+    : new WebSocket.Server(websocketOptionsOrServer);
 
   function handleConnection(socket: WebSocket, request: http.IncomingMessage) {
     if (
@@ -511,3 +510,7 @@ function isErrorEvent(obj: unknown): obj is WebSocket.ErrorEvent {
     hasOwnStringProperty(obj, 'type')
   );
 }
+
+function isWebSocketServer(obj: unknown): obj is WebSocketServer {
+  return isObject(obj) && typeof obj.on === 'function';
+}