Backend with Node.js

⚠️ Errors and robust validation

Centralize error handling in Express, custom error classes, and validate input with clear responses.

What you'll learn

• Centralize errors with a 4-parameter error middleware (err, req, res, next)
• Delegate errors from handlers with next(err) avoiding repeated try/catch
• Design an ApiError class that distinguishes operational errors (4xx) from bugs (5xx)
• Validate and sanitize input from req.body, req.query, and req.params, responding 400 with details

Lessons