Code Review

Code Review Skill

When reviewing code, follow this structured process:

1. Understand the Context

• What does this code do? Summarize its purpose in 1-2 sentences
• What files were changed and why?
• If reviewing a diff, understand both the before and after

2. Correctness

• Are there any logic bugs?
• Are edge cases handled (null, empty, zero, negative, boundary values)?
• Are error paths handled properly with meaningful error messages?
• Are return types and values correct?
• Are async operations handled properly (missing await, race conditions)?

3. Security

• SQL injection or NoSQL injection risks
• XSS vulnerabilities (unsanitized user input rendered in HTML)
• Hardcoded secrets, API keys, or credentials
• Insecure use of eval(), innerHTML, or dynamic code execution
• Missing authentication or authorization checks
• Sensitive data exposure in logs or error messages

4. Performance

• Unnecessary loops or O(n²) operations
• Missing database indexes for frequent queries
• N+1 query problems
• Large objects held in memory unnecessarily
• Missing pagination on list endpoints
• Expensive operations inside loops that could be batched

5. Readability & Maintainability

• Are variable and function names clear and descriptive?
• Are functions small and focused (single responsibility)?
• Is there duplicated code that should be extracted?
• Are magic numbers or strings replaced with named constants?
• Is complex logic commented or self-documenting?

6. Testing

• Are there tests for the new/changed code?
• Do tests cover happy path AND error cases?
• Are tests testing behavior, not implementation details?
• Are mocks used appropriately (not over-mocked)?

7. Project Standards

• Does the code follow the project's existing patterns and conventions?
• Are imports organized consistently?
• Does it match the linting and formatting rules?
• Are types properly defined (no unnecessary any in TypeScript)?

Output Format

For each issue found, report it as:

[SEVERITY] Category — File:Line Description of the issue.

Suggested fix:

// corrected code here

Severity levels:

• 🔴 CRITICAL — Bugs, security vulnerabilities, data loss risks. Must fix.
• 🟡 WARNING — Performance issues, missing error handling, potential problems. Should fix.
• 🟢 SUGGESTION — Readability, style, minor improvements. Nice to have.

Summary

End every review with:

1. Overall assessment — Is this safe to merge? (Yes / Yes with changes / No)
2. Critical issues count — How many must-fix items
3. Top 3 things done well — Always highlight positives
4. Top 3 improvements — Most impactful changes to make