Life & fun · alternatives · 2026

24 alternatives to Cancelable async primitives for JavaScript

Composable async primitives with cancelation, control over scheduling, and coroutines. Superior replacement for JS Promises. - mitranim/posterus

This is a JavaScript library that provides cancelable async primitives for developers. It allows programmers to create asynchronous operations that can be stopped or canceled before completion. The library is designed… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Cancelable async primitives for JavaScript launched in 2017; newer entries below may have overtaken it.

1. 1
   Async UI: A Rust UI Library Where Everything is a Future▲173

   2022 · wishawa.github.io · its alternatives →

2. 2
   Nsynjs – JS engine with stoppable threads and without callback hell▲51

   JavaScript engine + state machine with threads and without callbacks - amaksr/nsynjs

   2017 · github.com · its alternatives →

3. 3
   Kneden – Transpile ES7 Async/await to ES6 Promise Chains (Babel Plugin)▲76

   Transpile ES2017 async/await to vanilla ES6 Promise chains: a Babel plugin - babel/kneden

   2016 · github.com · its alternatives →

4. 4
   Coerce – Actor runtime for Rust using async/await and tokio channels▲155

   Actor runtime and distributed systems framework for Rust - LeonHartley/Coerce-rs

   2019 · github.com · its alternatives →

5. 5
   Fast.js – faster reimplementations of native JavaScript functions▲323

   Faster user-land reimplementations for several common builtin native JavaScript functions. - codemix/fast.js

   2014 · github.com · its alternatives →

6. 6
   Cross-browser asynchronous JS script loader w/callbacks▲45

   2012 · github.com · its alternatives →

7. 7
   Axax – Async iterator extensions for JavaScript▲74

   Async Iterator Extensions for JavaScript e.g. map, reduce, filter, flatMap, etc. - jamiemccrindle/axax

   2018 · github.com · its alternatives →

8. 8AJ
   A Javascript library to overcomplicate Five▲69

   2014 · jackdcrawford.github.io · its alternatives →

9. 9
   Crudlet.js – A common, streamable interface for synchronizing data▲94

   utility library for async iterable iterators. Contribute to crcn/mesh.js development by creating an account on GitHub.

   2015 · github.com · its alternatives →

10. 10
    Fast 2kB date library alternative to Moment.js with the same API▲122

    ⏰ Day.js 2kB immutable date-time library alternative to Moment.js with the same modern API - iamkun/dayjs

    2018 · github.com · its alternatives →

11. 11
    Neco – Coroutine Library for C▲145

    Concurrency library for C (coroutines). Contribute to tidwall/neco development by creating an account on GitHub.

    2024 · github.com · its alternatives →

12. 12
    Callbaxx.js – A utility library to bring callbacks to synchronous code▲43

    [Satire]🔥 JS utility library to bring classic callback style programming to synchronous code — ES6? More like ES Sucks. - scf4/callbaxx

    2018 · github.com · its alternatives →

13. 13
    Whirlwind – Async concurrent hashmap for Rust▲140

    Hey HN, this is Will and David from Fortress (https://news.ycombinator.com/item?id=41426998). We use a lot of async Rust internally, and created this library out of a need for an async-aware concurrent hashmap since there weren’t many available in the Rust ecosystem. Whirlwind is a sharded HashMap with a fully asynchronous API. Just as dashmap is a replacement for std::sync::RwLock, whirlwind aims to be a replacement for tokio::sync::RwLock. It has a similar design and performance characteristics to dashmap, but seems to perform better in read-heavy workloads with tokio's…

    2024 · github.com · its alternatives →

14. 14AL
    A library to record and intercept JavaScript at runtime▲118

    2017 · maierfelix.github.io · its alternatives →

15. 15FJ
    Forgo.js – a 4kb React alternative based on plain JS and DOM APIs▲110

    2021 · forgojs.org · its alternatives →

16. 16
    Kyushu – A self-hostable WASM sandbox for JavaScript workers▲89

    A self-hostable Wasm sandbox for JavaScript workers.

    Jun 2026 · kyushu.dev · its alternatives →

17. 17
    Asymmetric stackful cross-platform Coroutines in pure C▲39

    Single header stackful cross-platform coroutine library in pure C. - edubart/minicoro

    2021 · github.com · its alternatives →

18. 18CP
    Clojure parser and core library in JavaScript, live on CodeCombat▲57

    2014 · vickychijwani.github.io · its alternatives →

19. 19NN
    Nunjucks – Node templates with inheritance, asynchronous control▲43

    2013 · jlongster.github.io · its alternatives →

20. 20
    LazyPromise = Observable – Signals▲34

    A Promise-like primitive which is lazy/cancelable, has typed errors, and emits synchronously instead of on the microtask queue. In a way LazyPromise is what you get if you take an Observable and make it impossible to misuse it for what the Signals were built to do.

    Dec 2025 · github.com · its alternatives →

21. 21
    Waitasecond▲60

    Elegant JavaScript or TypeScript promises

    2023 · github.com · its alternatives →

22. 22
    Pure C Asynchronous HTTP Framework▲80

    Asynchronous C networking library with HTTP server, WebSockets, reverse proxy, HTTP/2 gRPC client, TLS and event loop. - Softmotions/iwnet

    2022 · github.com · its alternatives →

23. 23
    Aimless.js – the missing js randomness library▲64

    The missing JavaScript randomness library. Contribute to ChrisCavs/aimless.js development by creating an account on GitHub.

    2023 · github.com · its alternatives →

24. 24
    Parallel async JavaScript micro library in 25LOC▲7

    parallel async JS micro library in 25LOC. GitHub Gist: instantly share code, notes, and snippets.

    2014 · gist.github.com · its alternatives →

Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →