TypeScript Type Assertions

type-assertions is a JavaScript package providing a suite of assertion utilities specifically designed for testing TypeScript types at compile-time. It enables developers to write unit-like tests for their type definitions, ensuring that types behave as expected and catch regressions when refactoring complex type logic. The current stable version is 1.1.0, released in August 2019. This package has a very slow release cadence, with only two minor releases since its inception, indicating a stable and focused utility. Its primary differentiator is its reliance on the TypeScript compiler to validate assertions, providing compile-time feedback rather than runtime checks, which is ideal for validating type system intricacies.