# callbag/callbag

👜 A standard for JS callbacks that enables lightweight observables and iterables

Repository: https://github.com/callbag/callbag
Canonical: https://ross.abutalabs.com/products/callbag
License: NOASSERTION
License Family: other
Last push: 2023-02-27T19:29:12+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3148, "days_push": 1283, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1575, forks 39 (observed 2026-08-28T04:05:05.888446+00:00)

## What it is
Callbag is a lightweight specification/standard for JavaScript callbacks that enables minimal-overhead observables, iterables, and async iterables. It is intentionally not a library but a protocol definition (source/sink handshake, data delivery, and termination semantics) on which modular reactive utility packages can be built.

## Use cases
- implement lightweight observables in javascript
- standard for reactive streams with minimal memory allocations
- build modular stream operators as separate npm packages
- unify observables and async iterables under one callback protocol
- create custom reactive data sources and sinks
- learn how callback-based stream protocols work

## When to choose
- you want a tiny, dependency-free reactive streams standard with minimal overhead
- you need interoperability across callbag-based operator packages like callbag-basics
- you prefer composing your own reactive toolkit from small modular pieces
- you want one protocol covering observables, iterables, and async iterables

## When to avoid
- you need a batteries-included reactive library with rich operators out of the box
- you want extensive documentation, types, and community support like RxJS provides
- your team prefers established standards such as TC39 observable proposals or WHATWG streams
- you need guaranteed long-term maintenance, as the spec sees infrequent updates

## Facets
- artifact type: library
- maturity: stable
- function: streaming, concurrency, developer-tools
- domain: web-development, developer-tools, frontend, backend
- platform: browser, cross-platform
- tags: reactive-programming, observables, iterables, async-iterables, protocol-specification, callback-standard, functional-reactive, nodejs

## Member repositories
- callbag/callbag (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:05.888446+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 2026-08-30T03:57:35.526323+00:00, confidence not recorded.
  - readme: https://github.com/callbag/callbag (fetched 2026-08-28T04:05:05.888446+00:00, sha 3ee830c0faed)
  - registry_npm: https://registry.npmjs.org/callbag (fetched 2026-08-29T11:27:58.074844+00:00, sha a7028b4f46a5)
- Data as of 2026-08-30T08:39:29.467469+00:00.