# Peopleforrester Claude Dotfiles Refactoring Guide

> Refactoring Guide

- Skill: `tomevault-io/peopleforrester-claude-dotfiles-refactoring-guide` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/peopleforrester-claude-dotfiles-refactoring-guide`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/peopleforrester-claude-dotfiles-refactoring-guide/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/peopleforrester-claude-dotfiles-refactoring-guide

---


# Refactoring Guide

Improve code structure safely without changing behavior.

## When to Use

- User asks to "clean up" or "refactor" code
- Code smells detected during review
- Before adding new features to messy code
- Reducing duplication
- Improving readability

## Golden Rules

1. **Never refactor without tests** - Ensure behavior is preserved
2. **Small steps** - One change at a time, run tests after each
3. **No behavior changes** - Refactoring ≠ fixing bugs or adding features
4. **Commit often** - Easy to revert if something breaks

## Refactoring Process

```
1. Ensure tests exist and pass
   ↓
2. Identify the code smell
   ↓
3. Choose appropriate refactoring technique
   ↓
4. Make small change
   ↓
5. Run tests
   ↓
6. Commit if green, revert if red
   ↓
7. Repeat until done
```

## Common Code Smells

### Long Function

**Symptom**: Function > 20-30 lines, multiple responsibilities

**Refactoring**: Extract Method

```typescript
// Before
function processOrder(order: Order) {
  // Validate order (10 lines)
  // Calculate totals (15 lines)
  // Apply discounts (12 lines)
  // Update inventory (8 lines)
  // Send confirmation (10 lines)
}

// After
function processOrder(order: Order) {
  validateOrder(order);
  const totals = calculateTotals(order);
  const finalTotal = applyDiscounts(totals, order.discounts);
  updateInventory(order.items);
  sendConfirmation(order, finalTotal);
}
```

### Duplicate Code

**Symptom**: Similar code in multiple places

**Refactoring**: Extract to shared function

```typescript
// Before
function getUserName(user: User) {
  return `${user.firstName} ${user.lastName}`.trim();
}

function getCustomerName(customer: Customer) {
  return `${customer.firstName} ${customer.lastName}`.trim();
}

// After
function formatFullName(entity: { firstName: string; lastName: string }) {
  return `${entity.firstName} ${entity.lastName}`.trim();
}
```

### Long Parameter List

**Symptom**: Function with > 3-4 parameters

**Refactoring**: Introduce Parameter Object

```typescript
// Before
function createUser(
  name: string,
  email: string,
  age: number,
  address: string,
  phone: string,
  role: string
) { ... }

// After
interface CreateUserInput {
  name: string;
  email: string;
  age: number;
  address: string;
  phone: string;
  role: string;
}

function createUser(input: CreateUserInput) { ... }
```

### Nested Conditionals

**Symptom**: Deep if/else nesting

**Refactoring**: Guard Clauses / Early Returns

```typescript
// Before
function getDiscount(user: User) {
  if (user) {
    if (user.isActive) {
      if (user.isPremium) {
        return 0.2;
      } else {
        return 0.1;
      }
    }
  }
  return 0;
}

// After
function getDiscount(user: User) {
  if (!user) return 0;
  if (!user.isActive) return 0;
  if (user.isPremium) return 0.2;
  return 0.1;
}
```

### Magic Numbers/Strings

**Symptom**: Unexplained literal values in code

**Refactoring**: Extract Constant

```typescript
// Before
if (user.age >= 21) { ... }
if (status === 'PNDG') { ... }

// After
const MINIMUM_AGE = 21;
const ORDER_STATUS = {
  PENDING: 'PNDG',
  COMPLETE: 'CMPL',
} as const;

if (user.age >= MINIMUM_AGE) { ... }
if (status === ORDER_STATUS.PENDING) { ... }
```

### Feature Envy

**Symptom**: Method uses data from another class more than its own

**Refactoring**: Move Method

```typescript
// Before
class Order {
  getCustomerDiscount() {
    if (this.customer.loyaltyYears > 5) {
      return this.customer.baseDiscount * 1.5;
    }
    return this.customer.baseDiscount;
  }
}

// After
class Customer {
  getDiscount() {
    if (this.loyaltyYears > 5) {
      return this.baseDiscount * 1.5;
    }
    return this.baseDiscount;
  }
}
```

## Refactoring Techniques

| Smell | Technique |
|-------|-----------|
| Long function | Extract Method |
| Duplicate code | Extract Function/Class |
| Long parameter list | Parameter Object |
| Nested conditionals | Guard Clauses |
| Magic values | Extract Constant |
| Feature envy | Move Method |
| Large class | Extract Class |
| Primitive obsession | Value Object |
| Switch statements | Replace with Polymorphism |

## Safety Checklist

Before refactoring:
- [ ] Tests exist and pass
- [ ] Understand current behavior
- [ ] Identify specific smell to address

During refactoring:
- [ ] One change at a time
- [ ] Run tests after each change
- [ ] Commit when green

After refactoring:
- [ ] All tests still pass
- [ ] Code is more readable
- [ ] No behavior changed
- [ ] Review the diff

## When NOT to Refactor

- No test coverage exists (write tests first)
- Under tight deadline (technical debt is okay temporarily)
- Code is being deleted soon
- You don't understand the code fully

---
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