Show HN: Smartass – TypeScript test assertions with type-narrowing signatures

Category: library

Tags: typescript, testing, type-narrowing, assertions, developer-tools

Score: 6.3/10 (Innovation: 6, Technical: 6, Documentation: 7, Utility: 6)

Smartass is a TypeScript library providing assertion functions with type-narrowing signatures and composable matchers, enabling precise type inference in tests beyond traditional assertion libraries. It fills a niche gap for TypeScript developers who want stronger type safety without sacrificing readable test code. The project is technically solid with comprehensive assertion coverage, though it competes with existing solutions like zod or brand types for similar benefits.

Target audience: backend devs, frontend devs

Repository: https://github.com/KensioSoftware/smartass/ · TypeScript · AGPL-3.0 · 1 stars

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