# bcoe/c8

output coverage reports using Node.js' built in coverage

Repository: https://github.com/bcoe/c8
Canonical: https://ross.abutalabs.com/products/c8
Language: JavaScript
License: ISC
License Family: permissive
Last push: 2026-08-10T23:17:26+00:00

## Health v2 (maintenance only)
Score: 85/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 61, longevity 100
- inputs: {"age_days": 3233, "days_push": 23, "days_rel": 50, "gap_med": 290.0, "n_releases_24m": 3}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2119, forks 98 (observed 2026-08-28T04:06:16.442504+00:00)

## What it is
c8 is a CLI tool that generates code coverage reports for Node.js applications using Node's built-in V8 coverage output, formatted with Istanbul-compatible reporters. It works like nyc but requires no transpilation, simply wrapping any node command (e.g. `c8 node foo.js`).

## Use cases
- measure code coverage of node.js tests
- generate istanbul-style coverage reports without transpiling
- enforce coverage thresholds in CI
- check per-file coverage thresholds
- include untested files in coverage reports with --all

## When to choose
- you want fast, native V8 coverage for modern JavaScript without instrumentation/transpilation
- you need Istanbul-compatible reporters (lcov, html, text) for Node.js projects
- you want to enforce coverage thresholds in CI pipelines

## When to avoid
- you need coverage for browser-only code or non-Node runtimes
- you rely on nyc-specific instrumentation features or older Node versions lacking V8 coverage output
- you need coverage for languages other than JavaScript/TypeScript

## Facets
- artifact type: cli-tool
- maturity: active
- function: testing, benchmarking
- domain: testing, developer-tools
- platform: cli, cross-platform
- tags: code-coverage, v8-coverage, istanbul-reporters, nyc-alternative, javascript, command-line, nodejs

## Member repositories
- bcoe/c8 (main) score 85

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:16.442504+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 2026-08-30T02:53:01.796654+00:00, confidence not recorded.
  - readme: https://github.com/bcoe/c8 (fetched 2026-08-28T04:06:16.442504+00:00, sha 498a449a97e0)
  - registry_npm: https://registry.npmjs.org/c8 (fetched 2026-08-29T10:33:23.712275+00:00, sha 278b588fb7b8)
- Data as of 2026-08-30T08:39:29.467469+00:00.