Systematic code refactoring based on Martin Fowler's methodology. Use when users ask to refactor code, improve code structure, reduce technical debt, clean up l
复制下面这句话，粘贴给 Claude Code、Codex、Cursor 等 AI 编程工具，它会读取安装说明并在你确认后完成安装。
请阅读 https://ai.atlankj.com/install/asset/gh-refactor-c97affb08ff8 ，按照其中的说明把「refactor」安装到你（当前 AI 工具）中。执行前先告诉我将运行的命令和写入的位置，等我确认。
查看 AI 将读取的安装说明正在读取 GitHub 原文…
内容来自 GitHub 原始文件，由原作者维护。在 GitHub 查看
A systematic approach to refactoring code based on Martin Fowler's Refactoring: Improving the Design of Existing Code (2nd Edition). This skill emphasizes safe, incremental changes backed by tests.
"Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure." — Martin Fowler
Phase 1: Research & Analysis
↓
Phase 2: Test Coverage Assessment
↓
Phase 3: Code Smell Identification
↓
Phase 4: Refactoring Plan Creation
↓
Phase 5: Incremental Implementation
↓
Phase 6: Review & Iteration
Before starting, clarify:
Present findings to user:
"Refactoring without tests is like driving without a seatbelt." — Martin Fowler
Tests are the key enabler of safe refactoring. Without them, you risk introducing bugs.
Check for existing tests
# Look for test files
find . -name "*test*" -o -name "*spec*" | head -20
Run existing tests
# JavaScript/TypeScript
npm test
# Python
pytest -v
# Java
mvn test
Check coverage (if available)
# JavaScript
npm run test:coverage
# Python
pytest --cov=.
If tests exist and pass:
If tests are missing or incomplete: Present options:
If tests are failing:
For each function being refactored, ensure tests cover:
Use the "red-green-refactor" cycle:
Symptoms of deeper problems in code. They're not bugs, but indicators that the code could be improved.
See references/code-smells.md for the complete catalog.
| Smell | Signs | Impact |
|---|---|---|
| Long Method | Methods > 30-50 lines | Hard to understand, test, maintain |
| Duplicated Code | Same logic in multiple places | Bug fixes needed in multiple places |
| Large Class | Class with too many responsibilities | Violates Single Responsibility |
| Feature Envy | Method uses another class's data more | Poor encapsulation |
| Primitive Obsession | Overuse of primitives instead of objects | Missing domain concepts |
| Long Parameter List | Methods with 4+ parameters | Hard to call correctly |
| Data Clumps | Same data items appearing together | Missing abstraction |
| Switch Statements | Complex switch/if-else chains | Hard to extend |
| Speculative Generality | Code "just in case" | Unnecessary complexity |
| Dead Code | Unused code | Confusion, maintenance burden |
Automated Analysis (if scripts available)
python scripts/detect-smells.py <file>
Manual Review
Prioritization Focus on smells that:
Present to user:
For each smell, select an appropriate refactoring from the catalog.
See references/refactoring-catalog.md for the complete list.
| Code Smell | Recommended Refactoring(s) |
|---|---|
| Long Method | Extract Method, Replace Temp with Query |
| Duplicated Code | Extract Method, Pull Up Method, Form Template Method |
| Large Class | Extract Class, Extract Subclass |
| Feature Envy | Move Method, Move Field |
| Primitive Obsession | Replace Primitive with Object, Replace Type Code with Class |
| Long Parameter List | Introduce Parameter Object, Preserve Whole Object |
| Data Clumps | Extract Class, Introduce Parameter Object |
| Switch Statements | Replace Conditional with Polymorphism |
| Speculative Generality | Collapse Hierarchy, Inline Class, Remove Dead Code |
| Dead Code | Remove Dead Code |
Use the template at templates/refactoring-plan.md.
For each refactoring:
CRITICAL: Introduce refactoring gradually in phases.
Phase A: Quick Wins (Low risk, high value)
Phase B: Structural Improvements (Medium risk)
Phase C: Architectural Changes (Higher risk)
Before implementation:
"Change → Test → Green? → Commit → Next step"
For each refactoring step:
Pre-check
Make ONE small change
Verify
If tests pass (green)
If tests fail (red)
Each commit should be:
Example commit messages:
refactor: Extract calculateTotal() from processOrder()
refactor: Rename 'x' to 'customerCount' for clarity
refactor: Remove unused validateOldFormat() method
After each sub-phase, report to user:
Run complexity analysis before and after:
python scripts/analyze-complexity.py <file>
Present improvements:
Present final results:
Discuss with user:
Always pause and consult user when:
Before:
function processOrder(order) {
// 150 lines of code with:
// - Duplicated validation logic
// - Inline calculations
// - Mixed responsibilities
}
Refactoring Steps:
After:
function processOrder(order) {
validateOrder(order);
const total = calculateOrderTotal(order);
notifyCustomer(order, total);
return { order, total };
}
scripts/analyze-complexity.py - Analyze code complexity metricsscripts/detect-smells.py - Automated smell detectionLast Updated: August 4, 2026 Claude Code Version: 2.1.220 Sources: