Error Handling

Rationale

Consistent error handling improves reliability, debugging, and user experience. It helps prevent silent failures and makes troubleshooting easier.

Centralized Error Handling

Use a centralized approach for handling errors. Create error handler functions or modules to manage exceptions and log errors consistently.

Example (Node.js Express):

app.use((err, req, res, next) => {
  // Log error
  console.error(err);
  // Send user-friendly message
  res.status(500).json({ error: 'Internal server error' });
});

Example (Browser):

window.onerror = function(message, source, lineno, colno, error) {
  // Log error to monitoring service
  sendErrorToService({ message, source, lineno, colno });
};

Custom Errors

Define custom error classes for specific error types to improve clarity and debugging.

Example:

class ValidationError extends Error {
  constructor(message) {
    super(message);
    this.name = 'ValidationError';
  }
}
throw new ValidationError('Email is invalid');

Logging

Log errors and important events using a logging library or custom logger. Avoid exposing sensitive information in error messages.

Example:

// Good: Use a logging library
import winston from 'winston';
const logger = winston.createLogger({ /* ... */ });
logger.error('Something went wrong', error);

// Bad: Use console.log for errors in production
console.log('Error:', error);

• Avoid logging sensitive data.
• Use external monitoring tools (Sentry, Loggly) for production.

User-Friendly Error Messages

• Display clear, actionable error messages to users.
• Avoid technical jargon and stack traces in user-facing errors. Example:

  try {
  // ...
  } catch (e) {
  showError('Something went wrong. Please try again.');
  }

Best Practices

• Return user-friendly error messages.
• Test error handling in both development and production environments.
• Use custom error pages or dialogs for common errors (404, 500).
• Document error handling conventions for new team members.
• Monitor logs and set up alerts for critical errors.