refactoring

name	refactoring
description	Code refactoring patterns, clean code principles, and safe transformation techniques.
globs	["**/*.js","**/*.ts","**/*.py","**/*.java","**/*.go","**/*.rs"]
priority	85
tags	["workflow"]

Refactoring Best Practices

Before Refactoring

• Ensure tests exist and pass
• Understand the current behavior
• Make small, incremental changes
• Commit after each refactoring step
• Use feature flags for large refactors

Code Smells to Fix

• Long methods (> 30 lines) -> Extract method
• Large classes -> Extract class
• Long parameter lists -> Introduce parameter object
• Duplicate code -> Extract shared function
• Deep nesting -> Early returns / guard clauses
• Magic numbers -> Named constants
• God objects -> Single responsibility

Safe Refactoring Techniques

• Rename for clarity (variables, functions, classes)
• Extract method/function
• Inline temporary variables
• Replace conditional with polymorphism
• Move method to appropriate class
• Replace loop with pipeline (map/filter/reduce)
• Introduce null object pattern

Clean Code Principles

• Functions should do one thing
• Functions should be < 20 lines ideally
• No side effects in pure functions
• Use descriptive names (no abbreviations)
• Comments explain WHY, not WHAT
• DRY but don't over-abstract