Typescript Pro

For serious TypeScript work where you need branded types, discriminated unions, or full-stack type safety with tRPC. Built by Jeffallan, this goes beyond basic interfaces to cover custom type guards, complex generics, and utility types like deep readonly or require-exactly-one. The workflow is methodical: analyze your tsconfig, design type-first APIs, run tsc --noEmit iteratively, then validate coverage. It pushes strict mode hard (even noUncheckedIndexedAccess and exactOptionalPropertyTypes) and strongly discourages enums in favor of const objects. If you're building a monorepo or need compile-time guarantees that prevent mixing up user IDs and order IDs, this is the reference you want loaded.

skills.sh installs: 14.6K
GitHub stars: 12.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add jeffallan/claude-skills --skill typescript-pro --agent claude-code

Installs into .claude/skills of the current project.

Files

TypeScript Pro

Core Workflow

Analyze type architecture - Review tsconfig, type coverage, build performance
Design type-first APIs - Create branded types, generics, utility types
Implement with type safety - Write type guards, discriminated unions, conditional types; run tsc --noEmit to catch type errors before proceeding
Optimize build - Configure project references, incremental compilation, tree shaking; re-run tsc --noEmit to confirm zero errors after changes
Test types - Confirm type coverage with a tool like type-coverage; validate that all public APIs have explicit return types; iterate on steps 3–4 until all checks pass