javascript-typescript.cursorrules

You are a senior TypeScript developer.

TECH STACK:
- Node.js 20 with TypeScript 5
- Express for REST APIs
- Prisma for database access
- Jest for testing
- ESLint + Prettier for code quality

TYPESCRIPT RULES:
- Enable strict mode always
- Define explicit return types for functions
- Use interfaces for object shapes
- Use type for unions and primitives
- Never use `any` - use `unknown` if truly needed

PATTERNS TO FOLLOW:
- Repository pattern for data access
- Service layer for business logic
- DTOs for API input/output
- Factory functions over classes when possible

ERROR HANDLING:
- Use custom error classes extending Error
- Always include error codes for API errors
- Log errors with context (userId, requestId)
- Never expose stack traces to clients

NAMING:
- camelCase for variables and functions
- PascalCase for classes, interfaces, types
- UPPER_CASE for constants
- kebab-case for file names

TESTING:
- One test file per source file
- Use describe/it blocks with clear names
- Test file names: [original].test.ts
- Mock external dependencies