Work: @kensio/smartass npm package
The @kensio/smartass library is an open source TypeScript package that provides type narrowing
assertion functions. It uses TypeScript assertion signatures to provide type narrowing information
to the TypeScript compiler and IDE autocomplete.
The fluent expect().toBe() interface in Jest and Vitest is readable, but is unable to provide type
information to TypeScript and IDE autocomplete.
This library provides assertion functions with assertion signatures so that you can benefit from the extra type information.
As well as the standalone assertion functions, you can also use type narrowing matcher functions to compose an object structure.
GitHub: https://github.com/KensioSoftware/smartass
npm: https://www.npmjs.com/package/@kensio/smartass