Launched March 4, 2025
@wjfe/async-workers
Thread-safe cancellation and synchronization for web workers!
FreeAPIUI LibraryHelpers1,861 impressions#18 of its week
Before today, the only way to abort the work being done by a web worker was to terminate the worker. This is inconvenient because:
- Data may be lost that would have to be re-transmitted to a new worker instance after termination.
- Shared workers cannot be terminated.
This NPM package can provide a cancellation token based on Atomics.
Thread-safe cancellation and synchronization for Web Workers via Atomics
- for
- Web developers needing safe abort of worker tasks
- pricing
- open source
- license
- MIT
works withWeb WorkersAtomics
Key features
4 features of wjfe/async-workers
- Cancellation Token — Provides a token to abort worker tasks without terminating the worker
- Thread-Safe Sync — Uses Atomics for safe synchronization across workers
- NodeJS Support — Works in Node via a Worker polyfill like web-worker
- Cross-Origin Awareness — Handles environments without cross-origin isolation gracefully
Use cases
- Abort a long-running prime-number calculation in a shared worker
- Prevent data loss when restarting a worker after cancellation
- Synchronize multiple tasks using Atomics in a NodeJS server
wjfe/async-workers FAQ
Can I cancel a worker after it has started?+
No, cancellation is only possible before the worker starts due to lack of cross-origin isolation.
What if my site is cross-origin isolated?+
If cross-origin isolation is enabled, synchronization objects like SharedArrayBuffer can be used; otherwise they are unavailable.
Does this work in browsers that don’t support SharedArrayBuffer?+
Yes, but you can only cancel tasks before they start; pausing or mid-execution cancellation isn’t supported.
How do I use this library in NodeJS?+
Install a Worker polyfill such as the web-worker package, then import the async-workers module.
Summarized by DevHunt from wjsoftware.github.io · Sep 29, 2026. Details may change; check the official site.
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