Some things.

public/main.js

@@ -12,7 +12,14 @@ ws.onmessage = (event) => {
 function sendMessage() {
   const text = input.value;
   if (text.trim()) {
-    ws.send(text);
+    ws.send(
+      JSON.stringify({
+        type: "send",
+        data: {
+          content: text,
+        },
+      }),
+    );
     input.value = "";
   }
 }

src/sockets/chatSocket.js

@@ -4,7 +4,16 @@ function setupChatSocket(wss) {
   wss.on("connection", (ws) => {
     ws.send("Welcome.");
     ws.on("message", (message) => {
-      chatService.broadcast(wss, message, ws);
+      const data = JSON.parse(message);
+      if (data["type"] === "send") {
+        const sendEventPacket = JSON.stringify({
+          type: "send-event",
+          data: {
+            content: data["data"]["content"],
+          },
+        });
+        chatService.broadcast(wss, sendEventPacket, ws);
+      }
     });
   });
 }