added Chat-app

Chat-App/app.js

@@ -0,0 +1,37 @@
+const { log } = require('console');
+const express = require('express');
+const path=require('path');
+const app = express();
+const PORT = process.env.port || 3000;
+const server=app.listen(PORT, () => {
+    console.log(`Server is running on port ${PORT}.`);
+}
+)
+const io=require('socket.io')(server);
+
+app.use(express.static(path.join(__dirname, 'public')));
+
+let socketsConnected=new Set();
+
+io.on('connection', onConnected);
+
+
+function onConnected(socket){
+    socketsConnected.add(socket.id);
+    io.emit("clients-total", socketsConnected.size);
+    socket.on('disconnect', () => {
+    console.log("Socket disconnected: " + socket.id);
+    socketsConnected.delete(socket.id);
+    io.emit("clients-total", socketsConnected.size);
+    })
+
+    socket.on('message', (data) => {
+        // console.log(data);
+        socket.broadcast.emit('chat-message', data);
+    })
+
+    socket.on('feedback', (data) => {
+        socket.broadcast.emit('feedback', data);
+    })
+}
+