Comprehensive checklist for conducting thorough code reviews covering functionality, security, performance, and maintainability
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.
Before reviewing code, I'll help you understand:
Check if the code works correctly:
Assess code maintainability:
Check for security issues:
Look for performance issues:
Verify test coverage:
## 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 });
}
\`\`\`
## 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');
}
\`\`\`
## 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 };
}
\`\`\`
Symptoms: Code works for happy path but fails on edge cases Solution: Ask "What if...?" questions
Symptoms: Code exposes security risks Solution: Use security checklist
Symptoms: New code has no tests or inadequate tests Solution: Require tests for all new code
Symptoms: Reviewer can't understand what code does Solution: Request improvements
**Issue:** [Describe the problem]
**Current code:**
\`\`\`javascript
// Show problematic code
\`\`\`
**Suggested fix:**
\`\`\`javascript
// Show improved code
\`\`\`
**Why:** [Explain why this is better]
**Question:** [Your question]
**Context:** [Why you're asking]
**Suggestion:** [If you have one]
**Nice!** [What you liked]
This is great because [explain why]
@requesting-code-review - Prepare code for review@receiving-code-review - Handle review feedback@systematic-debugging - Debug issues found in review@test-driven-development - Ensure code has testsPro Tip: Use a checklist template for every review to ensure consistency and thoroughness. Customize it for your team's specific needs!
