# facebookarchive/emitter

A JS EventEmitter foundation for evented code

Repository: https://github.com/facebookarchive/emitter
Canonical: https://ross.abutalabs.com/products/facebookarchive-emitter
Language: JavaScript
License: NOASSERTION
License Family: other
Archived: true
Last push: 2021-07-01T23:23:56+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": 4871, "days_push": 1889, "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 1061, forks 120 (observed 2026-08-28T04:03:26.010711+00:00)

## What it is
A lightweight JavaScript EventEmitter library (npm package fbemitter) from Facebook that prioritizes speed and simplicity for event-driven code. It provides addListener, once, emit, and subscription-based listener removal, conceptually similar to Node's EventEmitter.

## Use cases
- implement pub/sub event handling in JavaScript
- replace Node's EventEmitter in browser code
- build event-driven architectures on the web
- manage listener subscriptions with easy removal
- create a foundation for custom event systems
- decouple components via emitted events

## When to choose
- you need a small, fast, dependency-free emitter for browser or Node
- you want subscription tokens for precise listener removal
- you're building larger event abstractions on a simple base

## When to avoid
- you need Node's native EventEmitter API compatibility
- you require advanced features like wildcard events or async listeners
- you want an actively developed library with ongoing releases

## Facets
- artifact type: library
- maturity: maintenance
- function: middleware, developer-tools
- domain: frontend, web-development, developer-tools
- platform: browser
- tags: event-emitter, pubsub, evented-architecture, fbemitter, observer-pattern, javascript, nodejs

## Member repositories
- facebookarchive/emitter (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:26.010711+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 2026-08-30T06:56:50.209733+00:00, confidence not recorded.
  - readme: https://github.com/facebookarchive/emitter (fetched 2026-08-28T04:03:26.010711+00:00, sha 0fd3a4f1a875)
- Data as of 2026-08-30T08:39:29.467469+00:00.