# jestjs/jest

Delightful JavaScript Testing.

Repository: https://github.com/jestjs/jest
Canonical: https://ross.abutalabs.com/products/jest
Homepage: https://jestjs.io
Language: TypeScript
License: MIT
License Family: permissive
Topics: javascript, testing, painless-javascript-testing, facebook, immersive, painless, expectation, easy, snapshot
Last push: 2026-08-25T08:07:05+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 83, longevity 100
- inputs: {"age_days": 4650, "days_push": 8, "days_rel": 117, "gap_med": 6, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 45474, forks 6731 (observed 2026-08-28T04:12:09.572495+00:00)

## What it is
Jest is a comprehensive JavaScript testing framework with a focus on simplicity, working out of the box with Babel, TypeScript, Node, React, Angular, and Vue projects. It bundles a test runner, assertion library, mocking system, snapshot testing, and code coverage into a single zero-config package.

## Use cases
- write unit tests for javascript code
- test a react application
- snapshot test large objects
- mock imported modules in tests
- generate code coverage reports
- run tests in watch mode while developing
- test typescript code without extra setup

## When to choose
- you want a batteries-included, zero-config test runner for a JavaScript or TypeScript project
- you need snapshot testing, mocking, and coverage without assembling separate tools
- you work with React, Angular, Vue, or Node and want first-class framework integration

## When to avoid
- you need browser-based end-to-end testing (use Playwright or Cypress)
- you prefer a lightweight, fast native ESM runner like Vitest for a Vite-based project
- your project is not JavaScript/TypeScript

## Facets
- artifact type: framework
- maturity: stable
- function: testing, e2e-testing, mocking, cli, developer-tools
- domain: testing, developer-tools, web-development, frontend
- platform: cli, cross-platform
- tags: snapshot-testing, code-coverage, test-runner, zero-config, watch-mode, unit-testing, mock-functions, typescript-support, javascript, nodejs

## Member repositories
- jestjs/jest (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:12:09.572495+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 2026-08-29T16:21:45.447537+00:00, confidence not recorded.
  - readme: https://github.com/jestjs/jest (fetched 2026-08-28T04:12:09.572495+00:00, sha a31a7132747f)
  - homepage: https://jestjs.io (fetched 2026-08-29T07:45:30.549777+00:00, sha c7d1e9a262bb)
  - site_page: https://jestjs.io/docs/getting-started (fetched 2026-08-29T07:45:30.559362+00:00, sha a21ba0f9bc8c)
  - site_page: https://jestjs.io/docs/next/getting-started (fetched 2026-08-29T07:45:30.561523+00:00, sha ce80d2c2ecfd)
  - site_page: https://jestjs.io/docs/30.4/getting-started (fetched 2026-08-29T07:45:30.563586+00:00, sha 3d70c7a9503d)
  - site_page: https://jestjs.io/docs/30.0/getting-started (fetched 2026-08-29T07:45:30.565742+00:00, sha 96942b39079f)
  - site_page: https://jestjs.io/docs/29.7/getting-started (fetched 2026-08-29T07:45:30.567997+00:00, sha b49274ff6f93)
  - site_page: https://archive.jestjs.io/docs/en/24.x/getting-started.html (fetched 2026-08-29T07:45:30.570132+00:00, sha 5994a0ece400)
  - site_page: https://archive.jestjs.io/docs/en/23.x/getting-started.html (fetched 2026-08-29T07:45:30.572029+00:00, sha dd62c02599d9)
  - site_page: https://archive.jestjs.io/docs/en/22.x/getting-started.html (fetched 2026-08-29T07:45:30.574004+00:00, sha a976f8e5d632)
- Data as of 2026-08-30T08:39:29.467469+00:00.