# jsverify/jsverify

Write powerful and concise tests. Property-based testing for JavaScript. Like QuickCheck.

Repository: https://github.com/jsverify/jsverify
Canonical: https://ross.abutalabs.com/products/jsverify
Homepage: http://jsverify.github.io/
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2021-04-05T23:16:55+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4730, "days_push": 1976, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1661, forks 85 (observed 2026-08-28T04:05:18.565519+00:00)

## What it is
JSVerify is a property-based testing library for JavaScript, inspired by Haskell's QuickCheck. It generates random test inputs, verifies user-defined invariants over many cases, and shrinks failing inputs to minimal counterexamples, integrating with frameworks like Mocha and Jasmine.

## Use cases
- property-based testing for javascript functions
- generate random test inputs automatically
- find minimal failing counterexamples with shrinking
- test invariants like sort idempotency
- use quickcheck-style tests with mocha
- write property tests in typescript

## When to choose
- you want QuickCheck-style property testing in JavaScript
- you need automatic input generation and shrinking
- you use Mocha, Jasmine, or another test framework and want framework-agnostic properties

## When to avoid
- you only need simple example-based unit tests
- you need a actively developed library with modern maintenance
- you need property testing with deep TypeScript type integration

## Facets
- artifact type: library
- maturity: maintenance
- function: testing, fuzzing, data-generation
- domain: testing, developer-tools
- platform: cross-platform
- tags: property-based-testing, quickcheck, generators, shrinking, mocha, jasmine, javascript, nodejs

## Member repositories
- jsverify/jsverify (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:18.565519+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:44:37.615731+00:00, confidence not recorded.
  - readme: https://github.com/jsverify/jsverify (fetched 2026-08-28T04:05:18.565519+00:00, sha 5d138e2f90a4)
  - homepage: http://jsverify.github.io/ (fetched 2026-08-29T11:17:17.015441+00:00, sha d890f4d2e953)
  - registry_npm: https://registry.npmjs.org/jsverify (fetched 2026-08-29T11:17:17.018943+00:00, sha 2a5b3d321baa)
- Data as of 2026-08-30T08:39:29.467469+00:00.