diff --git a/index.js b/index.js
index 38ccaf1..05f72f4 100644
--- a/index.js
+++ b/index.js
@@ -19,57 +19,76 @@ async function executeSet(message, ws) {
   if (!subject) {
     subject = collections[message.subject] = db.collection(message.subject);
   }
-  let newValue = {$set: {}};
-  newValue.$set[message.field + '.modifiedAt'] = Date.now();
-  newValue.$set[message.field + '.modifiedBy'] = 'anonymous';
-  newValue.$set[message.field + '.transientValue'] = message.value;
+  let newValue = { $set: {} };
+  newValue.$set[message.field + ".modifiedAt"] = Date.now();
+  newValue.$set[message.field + ".modifiedBy"] = "anonymous";
+  newValue.$set[message.field + ".transientValue"] = message.value;
 
-  await subject.updateMany(message.filter, newValue, { upsert: true })
+  await subject.updateMany(message.filter, newValue, { upsert: true });
 }
 
-wss.on('connection', function connection(ws) {
+wss.on("connection", function connection(ws) {
   connections.push(ws);
-  console.log('accepted new connection');
+  console.log("accepted new connection");
 
-  ws.on('error', console.error);
-  ws.on('close', e => {
-    console.log('closed a connection');
+  ws.on("error", console.error);
+  ws.on("close", (e) => {
+    console.log("closed a connection");
     connections.splice(connections.indexOf(ws), 1);
   });
 
-  ws.on('message', function message(data, isBinary) {
-    console.log('received a new message');
+  ws.on("message", function message(data, isBinary) {
+    console.log("received a new message");
+    console.log("test");
 
     try {
       let message = JSON.parse(data);
-      console.log('message action is ' + message.action);
+      console.log(message);
+      if (
+        message.filter &&
+        message.filter._id &&
+        typeof message.filter._id === "string"
+      ) {
+        try {
+          message.filter._id = new ObjectId(message.filter._id);
+          console.log(message.filter._id);
+        } catch (e) {
+          console.error("Invalid ObjectId in filter:", e);
+        }
+      }
+      console.log("message action is " + message.action);
 
       switch (message.action) {
-        case 'set':
+        case "set":
           executeSet(message, ws).catch(console.error);
           break;
-        case 'subscribe':
+        case "subscribe":
           let subject = collections[message.subject];
           if (!subject) {
-            subject = collections[message.subject] = db.collection(message.subject);
+            subject = collections[message.subject] = db.collection(
+              message.subject
+            );
           }
-          subject.find(message.filter, {}).toArray().then(r => {
-            ws.send(JSON.stringify({
-              subject: message.subject,
-              field: message.field,
-              filter: message.filter,
-              value: r.map(v => v[message.field])
-            }));
-          });
+          subject
+            .find(message.filter, {})
+            .toArray()
+            .then((r) => {
+              ws.send(
+                JSON.stringify({
+                  subject: message.subject,
+                  field: message.field,
+                  filter: message.filter,
+                  value: r.map((v) => v[message.field]),
+                })
+              );
+            });
 
           break;
       }
-
     } catch (e) {
-      console.error('error while processing message', e);
+      console.error("error while processing message", e);
       ws.send(JSON.stringify(e));
     }
   });
-
 });
 */
\ No newline at end of file