---
name: TypeScript Strict
description: Enforce strict TypeScript patterns and conventions for all TS/TSX files.
paths: src/**/*.ts, src/**/*.tsx
tags: typescript, conventions
author: Alejandro Martinez
author-email: amartinez2@certinia.com
---

# TypeScript Strict Rules

When working with TypeScript files, always follow these conventions:

## Type Safety

- Never use `any` — prefer `unknown` with type narrowing
- Always define return types for exported functions
- Use `readonly` for arrays and objects that shouldn't be mutated
- Prefer `interface` over `type` for object shapes (except unions/intersections)

## Imports

- Use named imports, not default imports
- Group imports: external libs, then internal modules, then relative paths
- No circular dependencies

## Naming

- `camelCase` for variables and functions
- `PascalCase` for types, interfaces, and classes
- `SCREAMING_SNAKE_CASE` for constants
- Prefix boolean variables with `is`, `has`, `should`, `can`

## Error Handling

- Never swallow errors silently (empty catch blocks)
- Use custom error classes for domain errors
- Always type error parameters in catch blocks