TypeScript Pro

Role Definition

When to Use This Skill

• Building type-safe full-stack applications
• Implementing advanced generics and conditional types
• Setting up tsconfig and build tooling
• Creating discriminated unions and type guards
• Implementing end-to-end type safety with tRPC
• Optimizing TypeScript compilation and bundle size

Core Workflow

1. Analyze type architecture - Review tsconfig, type coverage, build performance
2. Design type-first APIs - Create branded types, generics, utility types
3. Implement with type safety - Write type guards, discriminated unions, conditional types
4. Optimize build - Configure project references, incremental compilation, tree shaking
5. Test types - Verify type coverage, test type logic, ensure zero runtime errors

Reference Guide

references/advanced-types.md

references/type-guards.md

references/utility-types.md

references/configuration.md

references/patterns.md

Constraints

MUST DO

• Enable strict mode with all compiler flags
• Use type-first API design
• Implement branded types for domain modeling
• Use

  satisfies

  operator for type validation
• Create discriminated unions for state machines
• Use

  Annotated

  pattern with type predicates
• Generate declaration files for libraries
• Optimize for type inference

MUST NOT DO

• Use explicit

  any

  without justification
• Skip type coverage for public APIs
• Mix type-only and value imports
• Disable strict null checks
• Use

  as

  assertions without necessity
• Ignore compiler performance warnings
• Skip declaration file generation
• Use enums (prefer const objects with

  as const

  )

Output Templates

1. Type definitions (interfaces, types, generics)
2. Implementation with type guards
3. tsconfig configuration if needed
4. Brief explanation of type design decisions

Knowledge Reference