# mozilla/task.js

Beautiful concurrency for JavaScript

Repository: https://github.com/mozilla/task.js
Canonical: https://ross.abutalabs.com/products/taskjs
Homepage: http://taskjs.org
Language: JavaScript
License: NOASSERTION
License Family: other
Last push: 2019-03-28T03:38:53+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": 5804, "days_push": 2715, "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 1628, forks 73 (observed 2026-08-28T04:05:13.310074+00:00)

## What it is
task.js is a JavaScript library built on ES6 generators that provides a cooperative task scheduler and synchronizable events, enabling non-blocking I/O written in a synchronous style without callbacks. It was an early Mozilla experiment in making asynchronous JavaScript code look and read like sequential code.

## Use cases
- write async I/O without callbacks using generators
- run multiple I/O operations concurrently and join their results
- add timeouts to async operations with try/catch error handling
- avoid callback pyramids in pre-async/await JavaScript engines
- coordinate tasks with first-class synchronizable events

## When to choose
- you are stuck maintaining legacy JavaScript that must run on engines without async/await
- you want a minimal, educational example of generator-based cooperative scheduling

## When to avoid
- you are starting a new project - use native async/await and Promises instead
- you need a maintained library with active support or security updates
- your runtime already supports modern async syntax, which makes task.js redundant

## Facets
- artifact type: library
- maturity: abandoned
- function: concurrency, http-client, developer-tools
- domain: developer-tools, web-development, programming-languages
- platform: browser, cross-platform
- tags: generators, async-io, task-scheduler, cooperative-concurrency, es6, callbacks, nodejs, javascript

## Member repositories
- mozilla/task.js (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:13.310074+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 2026-08-30T03:48:20.552866+00:00, confidence not recorded.
  - readme: https://github.com/mozilla/task.js (fetched 2026-08-28T04:05:13.310074+00:00, sha 2a4ef282f092)
  - homepage: http://taskjs.org (fetched 2026-08-29T11:21:19.051845+00:00, sha 9ee39d3caf96)
  - site_page: https://taskjs.org/a-propos (fetched 2026-08-29T11:21:19.061003+00:00, sha 1f30b041f839)
- Data as of 2026-08-30T08:39:29.467469+00:00.