# JSMonk/hegel

An advanced static type checker

Repository: https://github.com/JSMonk/hegel
Canonical: https://ross.abutalabs.com/products/hegel
Homepage: https://hegel.js.org
Language: JavaScript
License: MIT
License Family: permissive
Topics: javascript, type-safety, typeinference
Archived: true
Last push: 2024-01-29T12:23:47+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": 2874, "days_push": 947, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2082, forks 57 (observed 2026-08-28T04:06:11.713149+00:00)

## What it is
Hegel is an advanced static type checker for JavaScript with optional type annotations, strong soundness checks, powerful type inference, and typed errors. It uses standard .d.ts files for library typings and requires no new language or special file extensions.

## Use cases
- check javascript code for type errors before runtime
- add optional type annotations to plain javascript
- catch runtime typeerrors statically
- infer types automatically without annotations
- annotate which errors a function can throw
- use existing d.ts typings with a javascript type checker

## When to choose
- you want a sound type system that guarantees no runtime TypeErrors, unlike TypeScript
- you want to type plain JavaScript without new syntax, file extensions, or a compile step
- you need strong type inference and typed errors in JavaScript

## When to avoid
- you need an actively maintained tool - the project is officially closed and no longer developed
- you need ecosystem maturity, editor integrations, or community support comparable to TypeScript or Flow
- you want a typed superset language that compiles to JavaScript

## Facets
- artifact type: library
- maturity: abandoned
- function: type-system, linter, developer-tools
- domain: programming-languages, developer-tools, web-development
- platform: cli, cross-platform
- tags: static-type-checker, javascript, type-inference, typed-errors, sound-type-system, discontinued, nodejs

## Member repositories
- JSMonk/hegel (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:11.713149+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 2026-08-30T02:55:54.955966+00:00, confidence not recorded.
  - readme: https://github.com/JSMonk/hegel (fetched 2026-08-28T04:06:11.713149+00:00, sha 36128c1ae7ce)
  - homepage: https://hegel.js.org (fetched 2026-08-29T10:36:16.779291+00:00, sha d1b2419973ed)
  - site_page: https://hegel.js.org/docs (fetched 2026-08-29T10:36:16.784869+00:00, sha 933e150b9c0a)
- Data as of 2026-08-30T08:39:29.467469+00:00.