# facebook/idx

Library for accessing arbitrarily nested, possibly nullable properties on a JavaScript object.

Repository: https://github.com/facebook/idx
Canonical: https://ross.abutalabs.com/products/idx
Language: JavaScript
License: MIT
License Family: permissive
Archived: true
Last push: 2024-01-10T18:53:12+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": 3473, "days_push": 966, "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 1687, forks 51 (observed 2026-08-28T04:05:22.177477+00:00)

## What it is
idx is a JavaScript utility for safely traversing arbitrarily nested, possibly nullable properties on objects and arrays, paired with a Babel plugin that compiles calls into efficient null checks. It is now deprecated in favor of native optional chaining.

## Use cases
- safely access deeply nested properties that may be null or undefined
- avoid long chains of && guards when reading nested object data
- traverse nullable arrays and objects in React props
- get null-safe property access with Flow or TypeScript type checking
- replace verbose null checks in legacy JavaScript codebases

## When to choose
- maintaining a legacy codebase that already uses idx and the Babel plugin
- working in an environment without optional chaining support and no upgrade path
- you need the specific behavior where an intermediate null value is returned rather than undefined

## When to avoid
- starting a new project - use native optional chaining (?.) instead
- your runtime already supports optional chaining
- you need maintained software with ongoing support

## Facets
- artifact type: library
- maturity: abandoned
- function: developer-tools
- domain: web-development, frontend, developer-tools
- platform: browser
- tags: optional-chaining, null-safety, babel-plugin, deprecated, flow, typescript, nodejs, javascript

## Member repositories
- facebook/idx (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:22.177477+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 2026-08-30T03:38:51.296311+00:00, confidence not recorded.
  - readme: https://github.com/facebook/idx (fetched 2026-08-28T04:05:22.177477+00:00, sha 2b74c8b8bdcb)
  - registry_npm: https://registry.npmjs.org/idx (fetched 2026-08-29T11:13:58.992773+00:00, sha 461da46859f8)
- Data as of 2026-08-30T08:39:29.467469+00:00.