Code Challenge - Backend Engineer Agaesh

.gitignore

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+# Node.js dependencies
+node_modules/
+
+# Logs
+*.log
+
+# Build output
+dist/
+
+# OS / editor files
+.DS_Store
+Thumbs.db
+.vscode/
+
+# Optional: lock file (depends on team policy)
+package-lock.jsons
+.env

Client.js

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+// client.js
+import WebSocket from 'ws';
+
+function connect() {
+  const socket = new WebSocket('ws://localhost:3000'); // adjust port if needed
+
+  socket.on('open', () => {
+    console.log('Connected to Problem 6 WebSocket');
+  });
+
+  socket.on('message', (data) => {
+    try {
+      const msg = JSON.parse(data);
+
+      if (msg.type === 'leaderboardUpdate') {
+        console.log('Leaderboard updated:');
+        msg.leaderboard.forEach(user => {
+          console.log(`${user.name}: ${user.score}`);
+        });
+      } else {
+        console.log('Received:', msg);
+      }
+    } catch (err) {
+      console.error('Failed to parse message:', data);
+    }
+  });
+
+  socket.on('close', () => {
+    console.log('Disconnected from WebSocket server, retrying in 5s...');
+    setTimeout(connect, 5000); // retry after 5 seconds
+  });
+
+  socket.on('error', (err) => {
+    console.error('WebSocket error:', err.message);
+    // Close and retry
+    socket.close();
+  });
+}
+
+// Initial connect attempt
+connect();

Index.js

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+import express from 'express';
+import { WebSocketServer } from 'ws';
+import { initWebSocket } from './WebSocket.js';
+
+import { sum_to_n_a, sum_to_n_b, sum_to_n_c } from './src/problem4/summation_solution.js';
+import CrudUser from '../code-challenge/src/problem5/CrudUser.js';
+import Architecture from './src/problem6/Architecture.js';
+
+import dotenv from 'dotenv';
+import helmet from 'helmet';
+
+dotenv.config(); // loads .env file into process.env
+
+const app = express();
+const PORT = process.env.PORT || 3000;
+
+app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
+app.use(helmet()); //to avoid clickjacking, XSS and browser based attacks
+
+app.get('/problem4', (req, res) => {
+  try {
+    const results = {
+      forLoop: sum_to_n_a(5),
+      reducer: sum_to_n_b(5),
+      recursion: sum_to_n_c(5)
+    };
+    res.json(results);
+  } catch (e) {
+    res.status(500).json({ error: e.message });
+  }
+});
+
+app.use('/problem5/users', CrudUser);
+app.use('/problem6', Architecture);
+
+const server = app.listen(PORT, () => {
+  console.log(`Server running at http://localhost:${PORT}`);
+});
+
+const wss = new WebSocketServer({ server });
+
+initWebSocket(wss);
+
+export { app };

WebSocket.js

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+let wss;
+
+export function initWebSocket(server) {
+  wss = server;
+
+  // Handle new connections
+  wss.on('connection', ws => {
+    console.log('Client connected to Problem 6');
+    ws.send(JSON.stringify({ message: 'Connected to Problem 6 live updates' }));
+  });
+}
+
+export function broadcastProblem6(data) {
+  if (!wss) return;
+
+  wss.clients.forEach(client => {
+    if (client.readyState === 1) {
+      client.send(JSON.stringify(data));
+    }
+  });
+}