claudekit/skills/refactoring/references/code-smells.md

Code Smells Detection Guide

Smell → Refactoring Map

Smell	Signal	Refactoring
Long function	>20-30 lines	Extract function
Long parameter list	>3-4 params	Introduce parameter object
Duplicated logic	Same code in 3+ places	Extract function, DRY
Deep nesting	>3 levels of indentation	Early return, extract function
Feature envy	Uses another class's data more than its own	Move method to the class with the data
Shotgun surgery	One change → edits in many files	Move related code together
Primitive obsession	Raw strings/dicts instead of types	Introduce dataclass/interface
Dead code	Unreachable or unused	Delete it (git has history)
God class	Class does too many things	Extract class by responsibility
Comments as deodorant	Comments explaining messy code	Refactor the code to be clear

Python-Specific Smells

• dict used as a struct → use @dataclass or TypedDict
• Missing type hints on public functions
• Manual __init__ boilerplate → @dataclass
• String constants → Enum
• Getter/setter methods → @property

TypeScript-Specific Smells

• any type → unknown + narrowing or generics
• Enum → as const object (better tree-shaking)
• Class hierarchy for variants → discriminated union
• Interface duplication → utility types (Pick, Omit, Partial)
• Index as key in lists → stable unique ID