# gotwarlost/istanbul

Yet another JS code coverage tool that computes statement, line, function and branch coverage with module loader hooks to transparently add coverage when running tests. Supports all JS coverage use cases including unit tests, server side functional tests and browser tests. Built for scale.

Repository: https://github.com/gotwarlost/istanbul
Canonical: https://ross.abutalabs.com/products/istanbul
Language: JavaScript
License: NOASSERTION
License Family: other
Archived: true
Last push: 2024-12-08T15:50:22+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 5103, "days_push": 633, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8655, forks 771 (observed 2026-08-28T04:10:24.040813+00:00)

## What it is
Istanbul is a JavaScript code coverage tool that computes statement, line, function, and branch coverage using module loader hooks to transparently instrument code during test runs. It provides both a CLI and a library API, with multiple report formats including HTML, LCOV, and Cobertura.

## Use cases
- measure code coverage of node.js unit tests
- instrument javascript files for browser test coverage
- generate HTML or LCOV coverage reports
- add server-side coverage via middleware
- run tests with coverage without changing the test runner

## When to choose
- you need coverage for a legacy JavaScript/Node.js project and are already using this tool
- you want statement, branch, and function coverage with multiple report formats

## When to avoid
- starting a new project - use the actively maintained istanbuljs (nyc) instead
- you need support for modern JavaScript syntax or recent Node.js versions

## Facets
- artifact type: cli-tool
- maturity: abandoned
- function: testing, developer-tools
- domain: testing, developer-tools
- platform: cli, browser
- tags: code-coverage, instrumentation, javascript, deprecated, test-coverage, nodejs

## Member repositories
- gotwarlost/istanbul (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:24.040813+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 2026-08-29T17:25:40.280068+00:00, confidence not recorded.
  - readme: https://github.com/gotwarlost/istanbul (fetched 2026-08-28T04:10:24.040813+00:00, sha 31f0f2a47d00)
  - registry_npm: https://registry.npmjs.org/istanbul (fetched 2026-08-29T08:26:19.396479+00:00, sha e5f4ceb30a93)
- Data as of 2026-08-30T08:39:29.467469+00:00.