Feedback on initial implementation

websockets/backend/backend.js

@@ -34,6 +34,9 @@ app.listen(port, () => {
 
 app.post("/message", (req, res) => {
   const bodyBytes = [];
+
+  // It's quite hard to read what this function is doing, because it does lots of things at different levels of abstraction.
+  // Can you think how to make this function only act at one level of abstraction (e.g. by using a middleware for some of the handling)?
   req.on("data", (chunk) => bodyBytes.push(...chunk));
   req.on("end", () => {
     const bodyString = String.fromCharCode(...bodyBytes);
@@ -56,6 +59,7 @@ app.post("/message", (req, res) => {
     }
     const newMessage = {
       messageText: body.messageText,
+      // Can you think of any problems with using a user-supplied timestamp here, vs calculating the timestamp on the server?
       timestamp: body.timestamp,
       likes: 0,
       dislikes: 0,
@@ -135,6 +139,7 @@ webSocketServer.on("request", (request) => {
   console.log(new Date() + " Connection accepted.");
   activeWsConnections.push(connection);
   connection.on("close", function (reasonCode, description) {
+    // This looks like a TODO you meant to do?
     // put removing connection from active connections array here
     console.log(
       new Date() + " Peer " + connection.remoteAddress + " disconnected."

websockets/frontend/client.js

@@ -3,6 +3,8 @@ const websocket = new WebSocket(
   "wss://droid-an-chat-application-backend.hosting.codeyourfuture.io"
 );
 
+// It looks like you're using websockets just to notify "there's something for you to fetch", which feels slower than including the messages in the websocket itself.
+// What do you think?
 websocket.addEventListener("open", () => {
   console.log("CONNECTED");
   fetchAllMessagesSince();
@@ -34,6 +36,7 @@ const postMessageToBackend = async () => {
   const messageText = inputMessage.value.trim();
 
   if (!messageText) {
+    // This feels like it would be handy to extract a named function for "show an error message and then remove it".
     feedbackMessage.textContent = "Text is required.";
     setTimeout(() => (feedbackMessage.textContent = ""), 5000);
     return;
@@ -140,6 +143,7 @@ const keepFetchingRatings = async () => {
 
 websocket.addEventListener("message", (mesEvent) => {
   const response = JSON.parse(mesEvent.data);
+  // How unique do you expect timestamps to be? Can you see any risks with this approach to identifying messages?
   if (!state.messages.some((mes) => mes.timestamp === response.timestamp)) {
     state.messages.push(response);
     render();