type-fest

Provide TypeScript utility types for complex type transformations and validation.

Updated Mar 13, 2026
One-click install
npx skills add https://github.com/refactory-lang/refactory-template --skill type-fest-refactory-lang
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: type-fest
Source: https://github.com/refactory-lang/refactory-template/tree/main/.claude/skills/type-fest
Command: npx skills add https://github.com/refactory-lang/refactory-template --skill type-fest-refactory-lang

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill simplifies complex TypeScript type manipulations, providing pre-built, robust utility types to avoid reinventing the wheel and improve type safety.

Core Features & Use Cases

  • Type Transformation: Deeply modify, merge, or reshape object types.
  • Validation & Constraints: Enforce type rules like "at least one field" or "exactly one field".
  • Type Inspection: Query type properties and create conditional types.
  • Use Case: Refactor a legacy JavaScript codebase to TypeScript by leveraging type-fest to precisely define complex data structures and ensure type safety across your application.

Quick Start

Use the type-fest skill to find the PartialDeep type and show an example of its usage.

Frequently Asked Questions about type-fest

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I make all properties of a complex TypeScript object optional, including nested ones?

For deep TypeScript type transformations, you can use the PartialDeep utility type to recursively mark all nested object properties as optional. This avoids reinventing the wheel with complex recursive conditional logic.

What is the best way to enforce an "at least one field" constraint in TypeScript?

To enforce validation and constraints like "at least one field" in TypeScript, leverage pre-built utility types for precise constraint enforcement. This ensures robust type safety across your data structures without manual validation logic.

Can I use advanced utility types when refactoring a large-scale JavaScript codebase to TypeScript?

Yes, advanced TypeScript utility types are designed for large-scale refactoring to ensure type safety. They provide pre-built solutions for complex type transformations, validation, and precise data structure definitions across your application.

Does type-fest support branded types and deep object manipulation?

Yes, type-fest supports branded types and deep object manipulation by providing a comprehensive suite of advanced TypeScript utility types. It addresses complex scenarios requiring deep modifications, conditional type logic, and precise constraint enforcement.

How do I query and inspect TypeScript type properties during complex transformations?

To query and inspect TypeScript type properties, use dedicated type inspection utility types to create conditional logic and inspect properties. This enables enhanced developer productivity and strict type safety in large-scale projects.