| name | typescript-security |
| description | Secure coding practices for TypeScript. Use when validating input, handling auth tokens, sanitizing data, or managing secrets and sensitive configuration. (triggers: **/*.ts, **/*.tsx, validate, sanitize, xss, injection, auth, password, secret, token) |
TypeScript Security
Priority: P0 (CRITICAL)
Security standards for TypeScript applications based on OWASP guidelines.
Implementation Guidelines
- Validation: Use
Zod, Joi, or class-validator at the API boundary. Always parse and validate user-controlled input before using. Use safeParse for error handling without throwing. Return 400 with structured errors on failure.
- Sanitization: Use
DOMPurify for HTML sanitization to prevent Cross-Site Scripting (XSS).
- Secrets: Store secrets in
.env (e.g., JWT_SECRET) or Secret Managers. NEVER commit them to Git.
- Vulnerabilities: Prevent SQL Injection using Parameterized Queries (e.g.,
pool.query('... WHERE id = $1', [id])) or Type-safe ORMs (Prisma/TypeORM). Use Prisma.sql for raw queries.
- Authentication: Use
Argon2id for password hashing. Implement JWT (via jsonwebtoken or jose) with HttpOnly and Secure cookies. Use RS256 for public/private key pairs and implement Refresh Token rotation.
- CORS: Configure
CORS with Strict Origin Whitelisting. Avoid origin: '*'.
- Encryption: Use
crypto (Node.js) or Web Crypto API for sensitive data. Avoid legacy algorithms like MD5/SHA1.
- Input Filtering: Sanitize
user-controlled input before using it in file paths or OS commands (Command Injection).
Verification
After typing validation schemas (Zod/joi) or auth guards, call getDiagnostics (typescript-lsp) to confirm type narrowing is correct before finalizing.
Anti-Patterns
- No
eval(): Avoid dynamic execution.
- No Plaintext: Never commit secrets.
- No Trust: Validate everything server-side.
References
See references/REFERENCE.md for Zod validation, secure cookie setup, JWT auth, security headers, and RBAC patterns.
