# tc39/proposal-optional-chaining

Repository: https://github.com/tc39/proposal-optional-chaining
Canonical: https://ross.abutalabs.com/products/proposal-optional-chaining
Homepage: https://tc39.github.io/proposal-optional-chaining/
Language: HTML
License Family: other
Archived: true
Last push: 2022-01-24T21:12:16+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": 3464, "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 4909, forks 70 (observed 2026-08-28T04:09:02.272545+00:00)

## What it is
The official TC39 ECMAScript proposal repository and spec text for the Optional Chaining operator (?.) in JavaScript, which reached Stage 4 and was merged into the language standard. It documents the motivation, syntax, and semantics of safe property access and optional method calls.

## Use cases
- understand how the ?. optional chaining operator works in JavaScript
- read the official spec text for optional chaining semantics
- learn why user.address?.street is safer than user.address.street
- see how optional chaining interacts with nullish coalescing
- compare optional chaining syntax across languages like C# and Swift
- check edge cases like delete a?.b and forbidden write contexts

## When to choose
- you need authoritative, normative spec details about ?. behavior
- you are implementing a JavaScript engine or transpiler
- you want the historical proposal document and prior-art comparison

## When to avoid
- you want a tutorial or beginner-friendly guide to modern JavaScript
- you need a runnable library or tool rather than a specification
- you are looking for the already-shipped feature in a JS runtime

## Facets
- artifact type: learning-resource
- maturity: stable
- function: programming-language, documentation
- domain: programming-languages, web-development
- platform: cross-platform
- tags: ecmascript, tc39, language-proposal, spec-text, optional-chaining, javascript-syntax, javascript, specifications, web-server

## Member repositories
- tc39/proposal-optional-chaining (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:02.272545+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 2026-08-29T18:18:05.240112+00:00, confidence not recorded.
  - readme: https://github.com/tc39/proposal-optional-chaining (fetched 2026-08-28T04:09:02.272545+00:00, sha 04e12689e109)
  - homepage: https://tc39.github.io/proposal-optional-chaining/ (fetched 2026-08-29T09:00:15.251374+00:00, sha e3b6687d517d)
- Data as of 2026-08-30T08:39:29.467469+00:00.