How to fix Error: Session store not properly configured in Node.js

# For Redis (recommended for production)
npm install connect-redis redis

# For MongoDB
npm install connect-mongo

# For file-based storage (development only)
npm install session-file-store

# For SQLite/PostgreSQL
npm install connect-sqlite3
# or
npm install connect-pg-simple

const express = require('express');
const session = require('express-session');
const RedisStore = require('connect-redis').default;
const { createClient } = require('redis');

const app = express();

// Initialize Redis client
const redisClient = createClient();
redisClient.connect(); // Important: connect before using

// Create store instance
const store = new RedisStore({
  client: redisClient,
  prefix: 'sess:',
});

// Configure express-session with the store
app.use(session({
  store: store,
  secret: 'your-secret-key',
  resave: false,
  saveUninitialized: false,
  cookie: {
    secure: process.env.NODE_ENV === 'production',
    httpOnly: true,
    maxAge: 1000 * 60 * 60 * 24 // 24 hours
  }
}));

const redis = require('redis');
const RedisStore = require('connect-redis').default;

const redisClient = redis.createClient({
  host: 'localhost',
  port: 6379,
});

// Handle connection events
redisClient.on('error', (err) => {
  console.error('Redis client error:', err);
});

redisClient.on('connect', () => {
  console.log('Redis client connected');
});

// Wait for connection before starting server
redisClient.connect().then(() => {
  const store = new RedisStore({ client: redisClient });
  app.use(session({ store, /* other options */ }));
  
  app.listen(3000, () => {
    console.log('Server running on port 3000');
  });
}).catch(err => {
  console.error('Failed to connect to Redis:', err);
  process.exit(1);
});

const session = require('express-session');
const FileStore = require('session-file-store')(session);

const store = new FileStore({
  path: './sessions',
  ttl: 86400, // Session lifetime in seconds
});

app.use(session({
  store: store,
  secret: 'development-key',
  resave: false,
  saveUninitialized: false,
}));

app.get('/test-session', (req, res) => {
  // Set session data
  if (!req.session.views) {
    req.session.views = 0;
  }
  req.session.views++;
  
  // Log to verify store interaction
  console.log('Session views:', req.session.views);
  console.log('Session ID:', req.sessionID);
  
  res.send(`Views: ${req.session.views}`);
});

app.get('/check-store', (req, res) => {
  // Verify store connection (varies by store type)
  if (req.sessionStore) {
    console.log('Store is configured:', req.sessionStore.constructor.name);
    res.send('Store is ready');
  } else {
    res.status(500).send('Store not configured');
  }
});

# Check installed versions
npm list express-session
npm list connect-redis
# (or whichever store you're using)

# Update to latest compatible versions
npm install express-session@latest
npm install connect-redis@latest

# Check package.json for peer dependency warnings
cat package.json | grep -A 5 'peerDependencies'