code-review-checklist

Code Review Checklist

Overview

Provide a systematic checklist for conducting thorough code reviews. This skill helps reviewers ensure code quality, catch bugs, identify security issues, and maintain consistency across the codebase.

When to Use This Skill

How It Works

Step 1: Understand the Context

Before reviewing code, I'll help you understand:

Step 2: Review Functionality

Check if the code works correctly:

Step 3: Review Code Quality

Assess code maintainability:

Step 4: Review Security

Check for security issues:

Step 5: Review Performance

Look for performance issues:

Step 6: Review Tests

Verify test coverage:

Examples

Example 1: Functionality Review Checklist

## Functionality Review

### Requirements
- [ ] Code solves the stated problem
- [ ] All acceptance criteria are met
- [ ] Edge cases are handled
- [ ] Error cases are handled
- [ ] User input is validated

### Logic
- [ ] No logical errors or bugs
- [ ] Conditions are correct (no off-by-one errors)
- [ ] Loops terminate correctly
- [ ] Recursion has proper base cases
- [ ] State management is correct

### Error Handling
- [ ] Errors are caught appropriately
- [ ] Error messages are clear and helpful
- [ ] Errors don't expose sensitive information
- [ ] Failed operations are rolled back
- [ ] Logging is appropriate

### Example Issues to Catch:

**❌ Bad - Missing validation:**
\`\`\`javascript
function createUser(email, password) {
  // No validation!
  return db.users.create({ email, password });
}
\`\`\`

**✅ Good - Proper validation:**
\`\`\`javascript
function createUser(email, password) {
  if (!email || !isValidEmail(email)) {
    throw new Error('Invalid email address');
  }
  if (!password || password.length < 8) {
    throw new Error('Password must be at least 8 characters');
  }
  return db.users.create({ email, password });
}
\`\`\`

Example 2: Security Review Checklist

## Security Review

### Input Validation
- [ ] All user inputs are validated
- [ ] SQL injection is prevented (use parameterized queries)
- [ ] XSS is prevented (escape output)
- [ ] CSRF protection is in place
- [ ] File uploads are validated (type, size, content)

### Authentication & Authorization
- [ ] Authentication is required where needed
- [ ] Authorization checks are present
- [ ] Passwords are hashed (never stored plain text)
- [ ] Sessions are managed securely
- [ ] Tokens expire appropriately

### Data Protection
- [ ] Sensitive data is encrypted
- [ ] API keys are not hardcoded
- [ ] Environment variables are used for secrets
- [ ] Personal data follows privacy regulations
- [ ] Database credentials are secure

### Dependencies
- [ ] No known vulnerable dependencies
- [ ] Dependencies are up to date
- [ ] Unnecessary dependencies are removed
- [ ] Dependency versions are pinned

### Example Issues to Catch:

**❌ Bad - SQL injection risk:**
\`\`\`javascript
const query = \`SELECT * FROM users WHERE email = '\${email}'\`;
db.query(query);
\`\`\`

**✅ Good - Parameterized query:**
\`\`\`javascript
const query = 'SELECT * FROM users WHERE email = $1';
db.query(query, [email]);
\`\`\`

**❌ Bad - Hardcoded secret:**
\`\`\`javascript
const API_KEY = 'sk_live_abc123xyz';
\`\`\`

**✅ Good - Environment variable:**
\`\`\`javascript
const API_KEY = process.env.API_KEY;
if (!API_KEY) {
  throw new Error('API_KEY environment variable is required');
}
\`\`\`

Example 3: Code Quality Review Checklist

## Code Quality Review

### Readability
- [ ] Code is easy to understand
- [ ] Variable names are descriptive
- [ ] Function names explain what they do
- [ ] Complex logic has comments
- [ ] Magic numbers are replaced with constants

### Structure
- [ ] Functions are small and focused
- [ ] Code follows DRY principle (Don't Repeat Yourself)
- [ ] Proper separation of concerns
- [ ] Consistent code style
- [ ] No dead code or commented-out code

### Maintainability
- [ ] Code is modular and reusable
- [ ] Dependencies are minimal
- [ ] Changes are backwards compatible
- [ ] Breaking changes are documented
- [ ] Technical debt is noted

### Example Issues to Catch:

**❌ Bad - Unclear naming:**
\`\`\`javascript
function calc(a, b, c) {
  return a * b + c;
}
\`\`\`

**✅ Good - Descriptive naming:**
\`\`\`javascript
function calculateTotalPrice(quantity, unitPrice, tax) {
  return quantity * unitPrice + tax;
}
\`\`\`

**❌ Bad - Function doing too much:**
\`\`\`javascript
function processOrder(order) {
  // Validate order
  if (!order.items) throw new Error('No items');
  
  // Calculate total
  let total = 0;
  for (let item of order.items) {
    total += item.price * item.quantity;
  }
  
  // Apply discount
  if (order.coupon) {
    total *= 0.9;
  }
  
  // Process payment
  const payment = stripe.charge(total);
  
  // Send email
  sendEmail(order.email, 'Order confirmed');
  
  // Update inventory
  updateInventory(order.items);
  
  return { orderId: order.id, total };
}
\`\`\`

**✅ Good - Separated concerns:**
\`\`\`javascript
function processOrder(order) {
  validateOrder(order);
  const total = calculateOrderTotal(order);
  const payment = processPayment(total);
  sendOrderConfirmation(order.email);
  updateInventory(order.items);
  
  return { orderId: order.id, total };
}
\`\`\`

Best Practices

✅ Do This

❌ Don't Do This

Complete Review Checklist

Pre-Review

Functionality

Security

Performance

Code Quality

Tests

Documentation

Git

Common Pitfalls

Problem: Missing Edge Cases

Symptoms: Code works for happy path but fails on edge cases

Solution: Ask "What if...?" questions

Problem: Security Vulnerabilities

Symptoms: Code exposes security risks

Solution: Use security checklist

Problem: Poor Test Coverage

Symptoms: New code has no tests or inadequate tests

Solution: Require tests for all new code

Problem: Unclear Code

Symptoms: Reviewer can't understand what code does

Solution: Request improvements

Review Comment Templates

Requesting Changes

**Issue:** [Describe the problem]

**Current code:**
\`\`\`javascript
// Show problematic code
\`\`\`

**Suggested fix:**
\`\`\`javascript
// Show improved code
\`\`\`

**Why:** [Explain why this is better]

Asking Questions

**Question:** [Your question]

**Context:** [Why you're asking]

**Suggestion:** [If you have one]

Praising Good Code

**Nice!** [What you liked]

This is great because [explain why]

Related Skills

Additional Resources

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Pro Tip: Use a checklist template for every review to ensure consistency and thoroughness. Customize it for your team's specific needs!