typescript

Write TypeScript code following these principles: ## Type Safety - Prefer discriminated unions for state representation - Use `as const satisfies` for configuration objects - Avoid `any` - use `unknown` with proper type narrowing - Use Zod or similar for runtime validation of external data ## Code Style - Use arrow functions over function declarations - Prefer immutable data structures - Use strict TypeScript compiler options ## Patterns ```typescript // Discriminated union for state type Result<T, E> = { success: true; data: T } | { success: false; error: E }; // Configuration with literal types preserved const config = { mode: 'production', port: 3000, } as const satisfies Config; ```