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

- Use when reviewing pull requests
- Use when conducting code audits
- Use when establishing code review standards for a team
- Use when training new developers on code review practices
- Use when you want to ensure nothing is missed in reviews
- Use when creating code review documentation

## How It Works

### Step 1: Understand the Context

Before reviewing code, I'll help you understand:
- What problem does this code solve?
- What are the requirements?
- What files were changed and why?
- Are there related issues or tickets?
- What's the testing strategy?

### Step 2: Review Functionality

Check if the code works correctly:
- Does it solve the stated problem?
- Are edge cases handled?
- Is error handling appropriate?
- Are there any logical errors?
- Does it match the requirements?

### Step 3: Review Code Quality

Assess code maintainability:
- Is the code readable and clear?
- Are names descriptive?
- Is it properly structured?
- Are functions/methods focused?
- Is there unnecessary complexity?

### Step 4: Review Security

Check for security issues:
- Are inputs validated?
- Is sensitive data protected?
- Are there SQL injection risks?
- Is authentication/authorization correct?
- Are dependencies secure?

### Step 5: Review Performance

Look for performance issues:
- Are there unnecessary loops?
- Is database access optimized?
- Are there memory leaks?
- Is caching used appropriately?
- Are there N+1 query problems?

### Step 6: Review Tests

Verify test coverage:
- Are there tests for new code?
- Do tests cover edge cases?
- Are tests meaningful?
- Do all tests pass?
- Is test coverage adequate?

## Examples

### Example 1: Functionality Review Checklist

```markdown
## 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

```markdown
## 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
- [ ] A