clean-code-ch03-functions

To check clean code best practices during code review, validate function size limits, single responsibility, abstraction levels, argument count, side effects, command-query separation, error handling, and DRY principles. Use a checklist-driven approach to enforce these rules incrementally.

A clean function should ideally be 20 lines or fewer. Keeping functions small ensures they remain readable, focused on a single responsibility, and easier to maintain as the codebase grows.

Refactor large functions by enforcing single responsibility principle (SRP) and extracting blended logic into smaller, focused units. Apply abstraction level discipline, reduce argument count, eliminate side effects, and ensure command-query separation.

Yes, you can use this clean code checklist for onboarding. It provides a repeatable process for evaluating function quality, helping new developers understand size limits, SRP, naming discipline, CQS, and error handling patterns through practical code reviews.

Functions cause unexpected side effects when they violate command-query separation or blend responsibilities. Enforcing clean code principles like SRP, proper abstraction levels, and exception-based error handling prevents hidden state modifications and improves predictability.

The best way to enforce command-query separation and DRY during refactoring is applying a checklist that ensures functions either perform actions or return data, not both, while eliminating duplicated logic through extraction and consistent abstraction levels.