refactoring-patterns

name	refactoring-patterns
description	Apply safe refactoring patterns to improve code structure without changing behavior. Use when cleaning up code, reducing technical debt, or improving maintainability.
category	development-practices
priority	medium
tokenEstimate	1000
agents	["qe-code-reviewer","qe-quality-analyzer","qe-test-refactorer"]
implementation_status	optimized
optimization_version	1
last_optimized	"2025-12-03T00:00:00.000Z"
dependencies	[]
quick_reference_card	true
tags	["refactoring","code-quality","technical-debt","maintainability","clean-code"]
trust_tier	2
validation	{"schema_path":"schemas/output.json","validator_path":"scripts/validate-config.json"}

Refactoring Patterns

<default_to_action> When refactoring:

1. ENSURE tests pass (never refactor without tests)
2. MAKE small change (one refactoring at a time)
3. RUN tests (must stay green)
4. COMMIT (save progress)
5. REPEAT

Safe Refactoring Cycle:

npm test               # Green ✅
# Make ONE small change
npm test               # Still green ✅
git commit -m "refactor: extract calculateTotal"
# Repeat

Code Smells → Refactoring:

Smell	Refactoring
Long method (>20 lines)	Extract Method
Large class	Extract Class
Long parameter list (>3)	Introduce Parameter Object
Duplicated code	Extract Method/Class
Complex conditional	Decompose Conditional
Magic numbers	Named Constants
Nested loops	Replace Loop with Pipeline

NEVER REFACTOR:

• Without tests (write tests first)
• When deadline is tomorrow
• Code you don't understand
• Code that works and won't be touched </default_to_action>

Quick Reference Card

Common Refactorings

Pattern	Before	After
Extract Method	50-line function	5 small functions
Extract Class	Class doing 5 things	5 single-purpose classes
Parameter Object	fn(a,b,c,d,e,f)	fn(options)
Replace Conditional	if (type === 'a') {...}	Polymorphism