# tc39/proposal-class-fields

Orthogonally-informed combination of public and private fields proposals

Repository: https://github.com/tc39/proposal-class-fields
Canonical: https://ross.abutalabs.com/products/proposal-class-fields
Homepage: https://arai-a.github.io/ecma262-compare/?pr=1668
Language: HTML
License Family: other
Archived: true
Last push: 2022-01-24T20:55:32+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3398, "days_push": 1682, "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 1724, forks 110 (observed 2026-08-28T04:05:27.985389+00:00)

## What it is
The TC39 ECMAScript proposal repository for class field declarations, combining public and private fields for JavaScript classes. It reached Stage 4 and defines the `x = 0` and `#private` field syntax now part of the JavaScript language standard.

## Use cases
- understand how class fields work in javascript
- learn private class fields with # syntax
- check define vs set semantics for public fields
- read the spec text for class field declarations
- reference the history of the class fields proposal

## When to choose
- you need authoritative spec details on public/private class fields
- you are implementing a JavaScript engine or transpiler
- you want to understand [[Define]] vs [[Set]] semantics

## When to avoid
- you want a tool or library rather than a specification document
- you need beginner tutorials rather than normative spec text

## Facets
- artifact type: learning-resource
- maturity: stable
- function: programming-language, documentation
- domain: programming-languages, web-development, frontend, documentation
- platform: cross-platform, browser
- tags: ecmascript, javascript, tc39, language-proposal, specification, class-fields, private-fields, stage-4, nodejs

## Member repositories
- tc39/proposal-class-fields (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:27.985389+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 2026-08-30T03:33:55.762402+00:00, confidence not recorded.
  - readme: https://github.com/tc39/proposal-class-fields (fetched 2026-08-28T04:05:27.985389+00:00, sha 3af45567ec10)
  - homepage: https://arai-a.github.io/ecma262-compare/?pr=1668 (fetched 2026-08-29T11:09:18.377065+00:00, sha c40c71d742f2)
- Data as of 2026-08-30T08:39:29.467469+00:00.