# .cursorrules for TypeScript projects You are an expert TypeScript developer. Follow these standards: ## Code Style - Use `const` by default, `let` only when reassignment is needed - Prefer `interface` over `type` for object shapes - Use discriminated unions for complex state - Always use explicit return types on exported functions - Prefer early returns over nested conditionals ## Error Handling - Use Result<T, E> pattern instead of throwing - All async functions must have error handling - Use custom error classes extending Error ## Naming - PascalCase: types, interfaces, components, classes - camelCase: variables, functions, methods - SCREAMING_SNAKE: constants - kebab-case: file names ## Testing - Test behavior, not implementation - Use `describe/it` naming: "it should [expected behavior]" - Prefer integration tests over unit tests for API routes - Mock at the boundary, not internally When I ask you to write code, follow these rules exactly.