type-challenges is a massive set of TypeScript type-level puzzles that turn the compiler into a playground for metaprogramming. Each challenge is a miniature kata where you implement types that transform other types—parsing strings, inferring tuples, mapping unions—without writing any runtime code. Problems are arranged from warm-ups to brain-twisters, letting developers build intuition about distributive conditional types, inference in extends, variance, and other corner cases of the type system. The repository includes tests for each puzzle so you get immediate, compiler-driven feedback when your solution is correct. As a result, it doubles as both training material and a living reference for advanced patterns used in real libraries. Many engineers report that solving a handful of these dramatically improves their ability to write safe, expressive APIs with minimal runtime overhead.
Features
- Hundreds of graded puzzles from basic to extreme
- Test-driven workflow powered by the TypeScript compiler
- Focus on type-level algorithms, parsing, and inference tricks
- Community solutions and discussions to compare approaches
- Great preparation for building high-fidelity library typings
- Zero runtime—everything happens in the type system