How do you handle errors in Express.js? What is the difference between operational errors and programmer errors?

Sample answer preview

## Error Handling Middleware Express error handlers have **4 parameters**: `(err, req, res, next)`. ```javascript // Error handler must be defined LAST app.use((err, req, res, next) => { console.error(err.stack); res.status(500).json({ error: 'Something went wrong!' }); }); ```…