TypeScript Security

Priority: P0 (CRITICAL)

Security standards for TypeScript applications based on OWASP guidelines.

Validate Input at Boundaries

• 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.

See references/REFERENCE.md for Zod validation schemas, secure cookie setup, and JWT auth patterns.

Prevent Injection and XSS

• Sanitization: Use

  DOMPurify

  for HTML sanitization to prevent Cross-Site Scripting (XSS).
• SQL Injection: Use Parameterized Queries (e.g.,

  pool.query('... WHERE id = $1', [id])

  ) or Type-safe ORMs (

  Prisma

  /

  TypeORM

  ). Use

  Prisma.sql

  for raw queries.
• Input Filtering: Sanitize

  user-controlled input

  before using it in file paths or OS commands (Command Injection).

Secure 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

  .
• Secrets: Store secrets in

  .env

  (e.g.,

  JWT_SECRET

  ) or Secret Managers. NEVER commit them to Git.
• 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.

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.