# ericelliott/rtype

Intuitive structural type notation for JavaScript.

Repository: https://github.com/ericelliott/rtype
Canonical: https://ross.abutalabs.com/products/rtype
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2019-02-10T03:19:13+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3987, "days_push": 2761, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1120, forks 38 (observed 2026-08-28T04:03:39.735451+00:00)

## What it is
Rtype is a structural type notation for JavaScript with a TypeScript-inspired syntax, designed primarily for API documentation and embeddable as strings for runtime reflection. It is an RFC-stage developer preview with no significant tooling yet.

## Use cases
- document JavaScript API function signatures with type notation
- embed type annotations in JS strings for runtime type checking
- write compiler-agnostic structural type interfaces
- describe function signatures in library docs
- prototype a lightweight alternative to TypeScript types

## When to avoid
- you need static type checking or mature tooling
- you want production-grade type safety - use TypeScript or Flow instead
- you need a stable, actively maintained specification

## Facets
- artifact type: library
- maturity: experimental
- function: type-system, documentation, parser
- domain: programming-languages, documentation, developer-tools
- platform: cross-platform
- tags: structural-typing, type-notation, rfc, runtime-reflection, api-documentation, javascript, nodejs

## Member repositories
- ericelliott/rtype (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:39.735451+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 2026-08-30T06:41:05.556075+00:00, confidence not recorded.
  - readme: https://github.com/ericelliott/rtype (fetched 2026-08-28T04:03:39.735451+00:00, sha b8b66aae98da)
  - registry_npm: https://registry.npmjs.org/rtype (fetched 2026-08-29T12:44:52.525099+00:00, sha e8ff2919ef1e)
- Data as of 2026-08-30T08:39:29.467469+00:00.