refactor-expert · diff
git:20260325.da398da to git:20260410.d55a9ea
24 added, 127 removed. Audit A to A.
---
name: refactor-expert
description: "Guide safe, incremental refactoring that improves code quality without changing behavior."
autoInvoke: false
priority: medium
triggers:
- "refactor"
- "code cleanup"
- "improve code"
- "refactor:analyze"
- "refactor:plan"
---
# Skill: Refactor Expert
- **Category:** Dev Expert
- **Used By:** All development agents
-
- ---
-
- ## Overview
-
- Guide safe, incremental refactoring that improves code quality without changing behavior.
+ Safe, incremental refactoring. Improve quality without changing behavior.
---
- ## Documentation Commands
-
- Generate analysis and implementation plans before refactoring:
-
- | Command | Purpose | Output |
- |---------|---------|--------|
- | `refactor:analyze <file>` | Code analysis document | `.claude/logs/refactors/{target}-analysis.md` |
- | `refactor:plan <file>` | Implementation plan | `.claude/logs/refactors/{target}-plan.md` |
- | `refactor:docs <file>` | Both documents | Analysis + Plan + Summary |
+ ## Commands
- **Templates:** `templates/refactor-analysis.md`, `templates/refactor-plan.md`
+ | Command | Output |
+ |---------|--------|
+ | `refactor:analyze <file>` | `.claude/logs/refactors/{target}-analysis.md` |
+ | `refactor:plan <file>` | `.claude/logs/refactors/{target}-plan.md` |
+ | `refactor:docs <file>` | Analysis + Plan + Summary |
+ | `refactor:quick <file>` | Skip approvals |
+ | `refactor:performance <file>` | Performance-focused |
+ | `refactor:structure <file>` | Structure-focused |
---
- ## 1. Refactoring Decision
+ ## Decision
| Signal | Action |
|--------|--------|
| Code smell detected | Identify specific smell |
| Tests passing | Safe to refactor |
| No tests | Write tests FIRST |
- | Large change needed | Break into small steps |
+ | Large change | Break into small steps |
**Golden Rule:** Never refactor and add features simultaneously.
---
- ## 2. Common Refactoring Patterns
-
- ### Extract Method
- ```typescript
- // Before
- function processOrder(order: Order) {
- // validate
- if (!order.items.length) throw new Error('Empty')
- if (!order.customer) throw new Error('No customer')
- // calculate
- let total = 0
- for (const item of order.items) {
- total += item.price * item.qty
- }
- return total
- }
-
- // After
- function processOrder(order: Order) {
- validateOrder(order)
- return calculateTotal(order.items)
- }
- ```
-
- ### Replace Conditional with Polymorphism
- ```typescript
- // Before
- function getPrice(type: string, base: number) {
- if (type === 'premium') return base * 0.8
- if (type === 'vip') return base * 0.7
- return base
- }
-
- // After
- interface PricingStrategy { calculate(base: number): number }
- class PremiumPricing implements PricingStrategy { calculate(base: number) { return base * 0.8 } }
- ```
-
- ### Simplify Conditional
- ```typescript
- // Before
- if (date.before(SUMMER_START) || date.after(SUMMER_END)) { charge = qty * winterRate }
- else { charge = qty * summerRate }
-
- // After
- const isSummer = !date.before(SUMMER_START) && !date.after(SUMMER_END)
- charge = qty * (isSummer ? summerRate : winterRate)
- ```
-
- ---
-
- ## 3. Code Smells → Refactoring
+ ## Code Smells -> Refactoring
| Smell | Refactoring |
|-------|-------------|
| Long Method | Extract Method |
| Large Class | Extract Class |
- | Long Parameter List | Introduce Parameter Object |
+ | Long Parameter List | Parameter Object |
| Duplicate Code | Extract Method/Class |
| Feature Envy | Move Method |
- | Data Clumps | Extract Class |
| Primitive Obsession | Replace with Object |
- | Switch Statements | Replace with Polymorphism |
- | Speculative Generality | Remove unused abstraction |
+ | Switch Statements | Polymorphism |
| Dead Code | Delete it |
---
- ## 4. Safe Refactoring Steps
+ ## Safe Process
```
- 1. Ensure tests pass ✅
- 2. Make ONE small change
- 3. Run tests ✅
+ 1. Ensure tests pass
+ 2. ONE small change
+ 3. Run tests
4. Commit
5. Repeat
```
- **Never:** Multiple changes between test runs.
-
- ---
-
- ## 5. Refactoring Checklist
-
- Before:
- - [ ] Tests exist and pass
- - [ ] Understand current behavior
- - [ ] Identify specific smell
-
- During:
- - [ ] One change at a time
- - [ ] Tests after each change
- - [ ] Commit frequently
-
- After:
- - [ ] All tests pass
- - [ ] Code cleaner
- - [ ] Behavior unchanged
-
- ---
-
- ## Best Practices
-
- ### Do's
- - Test first, refactor second
- - Small, incremental changes
- - Commit after each successful refactor
- - Use IDE refactoring tools
- - Document why (not what)
-
- ### Don'ts
- - Refactor without tests
- - Mix refactoring with features
- - Make large changes at once
- - Refactor code you don't understand
- - Over-refactor working code
+ Never multiple changes between test runs.
---
- ## Related Commands
+ ## Checklist
- - `refactor <file>` - Full refactoring workflow
- - `refactor:analyze <file>` - Analysis document only
- - `refactor:plan <file>` - Implementation plan only
- - `refactor:docs <file>` - Both documents
- - `refactor:quick <file>` - Skip approvals
- - `refactor:performance <file>` - Performance-focused
- - `refactor:structure <file>` - Structure-focused
+ **Before:** Tests exist and pass, understand current behavior, identify smell.
+ **During:** One change at a time, test after each, commit frequently.
+ **After:** All tests pass, code cleaner, behavior unchanged.
---
-