diff --git a/SyNode/SpiderMonkey.pas b/SyNode/SpiderMonkey.pas
index 227aed0ec..1db3573fd 100644
--- a/SyNode/SpiderMonkey.pas
+++ b/SyNode/SpiderMonkey.pas
@@ -486,7 +486,18 @@ interface
   PJSStringFinalizer = ^JSStringFinalizer;
 
 // jsid
-  jsid = size_t;
+  JSIdType = (
+    JSID_TYPE_STRING = $0,
+    JSID_TYPE_INT    = $1,
+    JSID_TYPE_VOID   = $2,
+    JSID_TYPE_SYMBOL = $4
+  );
+  jsid = record
+    asBits: size_t;
+    function isString: Boolean;
+    function asJSString: PJSString;
+  end;
+
   TjsidVector = array[0..(MaxInt div sizeof(jsid))-2] of jsid;
   PjsidVector = ^TjsidVector;
 
@@ -5029,6 +5040,24 @@ function JSArgRec.getThisObject(cx: PJSContext): PJSObject;
   Result := this[cx].asObject;
 end;
 
+{ jsid }
+
+const
+  JSID_TYPE_MASK = $7;
+
+function jsid.isString: Boolean;
+begin
+  Result := JSIdType(asBits and JSID_TYPE_MASK) = JSID_TYPE_STRING;
+end;
+
+function jsid.asJSString: PJSString;
+begin
+{$ifdef WITHASSERT}
+  Assert(isString);
+{$endif}
+  Result := PJSString(asBits);
+end;
+
 { JSIdArray }
 
 procedure JSIdArray.init(cx: PJSContext);
diff --git a/SyNode/SyNodeRemoteDebugger.pas b/SyNode/SyNodeRemoteDebugger.pas
index a8bfb8353..8695854df 100644
--- a/SyNode/SyNodeRemoteDebugger.pas
+++ b/SyNode/SyNodeRemoteDebugger.pas
@@ -438,6 +438,7 @@ procedure TSMRemoteDebuggerCommunicationThread.HandleMessage(const request: Vari
   data: RawUTF8;
   i: integer;
   debuggerIndex: integer;
+  debugger: TSMDebugger;
   Writer: TTextWriter;
   engine: TSMEngine;
 begin
@@ -449,32 +450,33 @@ procedure TSMRemoteDebuggerCommunicationThread.HandleMessage(const request: Vari
         fParent.fDebuggers.Safe.Lock;
         try
           for I := 0 to fParent.fDebuggers.Count - 1 do begin
-            engine := fParent.fManager.EngineForThread(TSMDebugger(fParent.fDebuggers[i]).fSmThreadID);
+            debugger := TSMDebugger(fParent.fDebuggers[i]);
+            engine := fParent.fManager.EngineForThread(debugger.fSmThreadID);
             if engine <> nil then begin
               // Actor represent debug thread here, setting proper name with coxtext thread id
               // Writer.AddShort('{"actor":"server1.conn1.addon');
               // Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fIndex);
               Writer.AddShort('{"actor":"');
-              Writer.AddShort(TSMDebugger(fParent.fDebuggers[i]).fDebuggerName);
+              Writer.AddShort(debugger.fDebuggerName);
               Writer.AddShort('.conn1.thread_');
               { TODO : check that in multithread mode this field equal thread id with js context that we debug, otherwire replace with proper assigment }
-              Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fSmThreadID);
+              Writer.Add(debugger.fSmThreadID);
               // id should be addon id, value from DoOnGetEngineName event
               // Writer.AddShort('","id":"server1.conn1.addon');
               // Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fIndex);
               Writer.AddShort('","id":"');
-              Writer.AddString(TSMDebugger(fParent.fDebuggers[i]).fNameForDebug);
+              Writer.AddString(debugger.fNameForDebug);
               Writer.AddShort('","name":"');
-              Writer.AddString(TSMDebugger(fParent.fDebuggers[i]).fNameForDebug);
+              Writer.AddString(debugger.fNameForDebug);
               // url most likly should be addon folder in format: file:///drive:/path/
               // Writer.AddShort('","url":"server1.conn1.addon');
               // Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fIndex);
               { TODO : replace with path generation, should be context home dir in format file:///drive:/path/ }
-              Writer.AddShort('","url":"file:///' + StringReplaceAll(TSMDebugger(fParent.fDebuggers[i]).fWebAppRootPath, '\', '/'));
+              Writer.AddShort('","url":"file:///' + StringReplaceAll(debugger.fWebAppRootPath, '\', '/'));
               Writer.AddShort('","debuggable":');
-              Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fCommunicationThread = nil);
+              Writer.Add(debugger.fCommunicationThread = nil);
               Writer.AddShort(',"consoleActor":"console');
-              Writer.Add(TSMDebugger(fParent.fDebuggers[i]).fIndex);
+              Writer.Add(debugger.fIndex);
               Writer.AddShort('"},');
             end;
           end;
@@ -574,7 +576,7 @@ procedure TSMRemoteDebuggerCommunicationThread.sockWrite(const packet: RawUTF8);
   fCommunicationSock.SockSend(@tmp[1], length(tmp));
   fCommunicationSock.SockSend(@sep[1], length(sep));
   fCommunicationSock.SockSend(@packet[1], length(packet));
-  fCommunicationSock.SockSendFlush;
+  fCommunicationSock.SockSendFlush('');
 end;
 
 procedure TSMRemoteDebuggerCommunicationThread.startListening(socket: TCrtSocket);