functype-developer

Implementing a new functional data structure in TypeScript requires following functype's constructor-based, immutable design pattern. Use the provided template script to generate boilerplate, then implement required functional interfaces like Functor and Monad, add comprehensive tests with Vitest, and validate against functional laws using pnpm validate before committing.

The Base pattern is functype's Scala-inspired architectural approach that enforces strict typing without relying on any, ensuring type safety and consistency across the library. It works with Companion utilities and higher-kinded types to provide a robust foundation for immutable data structure design.

Generate boilerplate for a new type by running the new-type-template.sh script with your type name, for example ./claude/skills/functype-developer/scripts/new-type-template.sh Result. The script creates constructor definitions, companion methods, and functional interface stubs tailored to functype's architecture.

Yes, functype integrates with standard TypeScript tooling including pnpm for package management, Prettier for formatting, ESLint for linting, and Vitest for testing. Ensure your project supports these tools and follows constructor-based, immutable design principles for consistency.

New functype types must implement core functional interfaces including Functor for mapping, Monad for sequential composition, and Foldable for iteration. The Skill provides checklists and examples for each interface to ensure functional laws are satisfied and library consistency is maintained.

Add comprehensive tests using Vitest covering your type's behavior and functional law compliance. Run pnpm validate to execute the full validation workflow including type checking, linting, formatting, and test execution before committing your changes.