# acornjs/acorn

A small, fast, JavaScript-based JavaScript parser

Repository: https://github.com/acornjs/acorn
Canonical: https://ross.abutalabs.com/products/acorn
Language: JavaScript
License Family: other
Last push: 2026-07-28T06:47:35+00:00

## Health v2 (maintenance only)
Score: 75/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 94, release rhythm 35, longevity 100
- inputs: {"age_days": 5091, "days_push": 36, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 11440, forks 1043 (observed 2026-08-28T04:10:47.004121+00:00)

## What it is
Acorn is a small, fast JavaScript parser written entirely in JavaScript that produces an ECMAScript syntax tree (AST). It ships as three packages: the main parser, an error-tolerant loose parser, and a syntax tree walker, and supports plugins for parsing JavaScript dialects like JSX.

## Use cases
- parse JavaScript source code into an AST
- build a linter or code analysis tool for JavaScript
- write a transpiler or code transformer
- parse incomplete or broken JavaScript with error tolerance
- traverse and inspect JavaScript syntax trees
- add support for JSX or other JS dialects via plugins

## When to choose
- you need a lightweight, dependency-free JavaScript parser in JS itself
- you are building tooling like linters, minifiers, bundlers, or formatters
- you need a plugin system to parse JavaScript dialects
- you need error-tolerant parsing of broken code via acorn-loose

## When to avoid
- you need to parse languages other than JavaScript/ECMAScript
- you need the absolute fastest native parser and can accept a compiled dependency
- you need a full compiler framework with code generation built in

## Facets
- artifact type: library
- maturity: stable
- function: parser, developer-tools
- domain: parsers, programming-languages, developer-tools, web-development
- platform: browser
- tags: ecmascript, ast, syntax-tree, javascript-parser, error-tolerant-parsing, nodejs, javascript

## Member repositories
- acornjs/acorn (main) score 75

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:47.004121+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 2026-08-29T17:15:36.071105+00:00, confidence not recorded.
  - readme: https://github.com/acornjs/acorn (fetched 2026-08-28T04:10:47.004121+00:00, sha d7ad308ad2e0)
  - registry_npm: https://registry.npmjs.org/acorn (fetched 2026-08-29T08:14:38.152806+00:00, sha f9d3e5ea808c)
- Data as of 2026-08-30T08:39:29.467469+00:00.