workerpool

# workerpool history https://github.com/josdejong/workerpool ## 2025-10-21, version 10.0.0 BREAKING CHANGES: - Feat: implement `queueStrategy` option (FIFO / LIFO / custom) (#518, #517). This is a new feature without changes in the public API, but the internal property `pool.tasks` is changed into `pool.taskQueue`. So, changes are required if you rely on this internal property. Thanks @amaneru55 - Feat: introduce a new `TerminateError` class to differentiate between a crash and a regular error (see #519, #520). The `TerminateError` class extends from the class `Error` so no breaking changes in that regard. But some of the error messages are changed so if you have code that depends on the exact error messages you may need to change your code accordingly. Thanks @Julusian. ## 2025-09-10, version 9.3.4 - Fix: #516 improve error handling for errors containing nested classes by using their `.toJSON` method when available. ## 2025-06-27, version 9.3.3 - Fix: #479 terminate worker even if abortListener resolved (#507). Thanks @joshLong145. ## 2025-05-29, version 9.3.2 - Fix: #505 npm package missing `/src/generated/` files. ## 2025-05-29, version 9.3.1 - Fix: #505 npm package missing `/src/generated/` files. ## 2025-05-28, version 9.3.0 - Feat: support for events and std streams to parents from an abort handler (#478). Thanks @joshLong145. - feat: improve compatibility with standard Promise type (#504). Thanks @joshkel. ## 2024-10-11, version 9.2.0 - Feat: implement support for abort handlers in the workers (#448). Thanks @joshLong145. - Feat: implement `Promise.finally()` on the custom promise class (#388). Thanks @joshLong145 and @wmertens. - Fix #460: `vite` example not working (#461). Thanks @datashaman. ## 2024-06-28, version 9.1.3 - Fix transferring from the worker (#455). Thanks @LeonidPolukhin. ## 2024-06-04, version 9.1.2 - Fix: #446 ensure the library can be used with older browsers. ## 2024-04-06, version 9.1.1 - Fix: events not emitted when using (#439). Thanks @t0oF-azpn. ## 2024-01-18, version 9.1.0 - Support capturing the stdout/stderr streams from the workers (#425, #423). Thanks @cpendery. ## 2023-12-22, version 9.0.4 - Improve the logic to detect the Node.js platform (#421). Thanks @tamuratak. ## 2023-12-20, version 9.0.3 - Improve types: unwrap Promise types (#419). Thanks @joshkel. ## 2023-12-19, version 9.0.2 - Export the `Proxy` type (see #417). Thanks @tamuratak. - Use workerpool's `Promise` type definition (see #417). Thanks @tamuratak. ## 2023-12-18, version 9.0.1 - Export the types `Pool`, `WorkerPoolOptions`, and `WorkerRegisterOptions`, see #416. Thanks @joshkel. ## 2023-12-18, version 9.0.0 BREAKING CHANGE: the library now comes with TypeScript type definitions included. There may be minor differences between the new, embedded type definitions and the implementation from `@types/workerpool` that was needed before. For example, `type WorkerPool` is called `type Pool` now. - Generate TypeScript types from JSDoc comments. Thanks @tamuratak. ## 2023-10-25, version 8.0.0 BREAKING CHANGE: the library now throws an Error when passing unknown or inherited properties for `workerOpts`, `workerThreadOpts` and `forkOpts`. - Fix: throw an error in case of unknown properties or inherited properties in `workerOpts`, `workerThreadOpts` and `forkOpts` to protect against security issues related to prototype pollution (see ea5368c5e53d97120b952ffad151a318c1ff073c). - Fix: #56 document the return type of all functions. - Docs: added a full usage example with Vite and Webpack5 (#408), thanks @KonghaYao. ## 2023-10-25, version 7.0.0 BREAKING CHANGE: The setup to bundle `workerpool` has been replaced. This should be a drop-in replacement, but it may have impact depending on your setup. - Switched build setup from Webpack to Rollup, see #403. Thanks @KonghaYao. ## 2023-10-11, version 6.5.1 - Fix: `workerThreadOpts` not working when `workerType: auto`, see #357. ## 2023-09-13, version 6.5.0 - Implement support for passing options to web workers constructors (#400, #322). Thanks @DonatJR. ## 2023-08-21, version 6.4.2 - Fix: a bug in the timeout of termination (#395, #387). Thanks @Michsior14. ## 2023-08-17, version 6.4.1 - Fix: worker termination before it's ready (#394, #387). Thanks @Michsior14. ## 2023-02-24, version 6.4.0 - Support transferable objects (#3, #374). Thanks @Michsior14. - Implement a new callback `onTerminate` at the worker side, which can be used to clean up resources, and an option `workerTerminateTimeout` which forcefully terminates a worker if it doesn't finish in time (#353, #377). Thanks @Michsior14. - Pass `workerThreadOpts` to the `onTerminateWorker` callback (#376). Thanks @Michsior14. ## 2022-11-07, version 6.3.1 - Fix #318: debug ports not being released when terminating a pool. ## 2022-10-24, version 6.3.0 - Implement option `workerThreadOpts` to pass options to a worker of type `thread`, a `worker_thread` (#357, fixes #356). Thanks @galElmalah. ## 2022-04-11, version 6.2.1 - Fix #343: `.terminate()` sometimes throwing an exception. ## 2022-01-15, version 6.2.0 - Implement callbacks `onCreateWorker` and `onTerminateWorker`. Thanks @forty. - Fix #326: robustness fix when terminating a workerpool. ## 2021-06-17, version 6.1.5 - Fix v6.1.4 not being marked as latest anymore on npm due to bug fix release v2.3.4. ## 2021-04-05, version 6.1.4 - Fix terminating a pool throwing an error when used in the browser. Regression introduced in `v6.1.3`. ## 2021-04-01, version 6.1.3 - Fix #147: disregard messages from terminated workers. Thanks @hhprogram and @Madgvox. ## 2021-03-09, version 6.1.2 - Fix #253, add `./src` again in the published npm package, reverting the change in `v6.1.1` (see also #243). ## 2021-03-08, version 6.1.1 - Remove redundant `./src` folder from the published npm package, see #243. Thanks @Nytelife26. ## 2021-01-31, version 6.1.0 - Implemented support for sending events from the worker to the main thread, see #51, #227. Thanks @Akryum. - Fix an issue in Node.js nightly, see #230. Thanks @aduh95. - Fix #232 `workerpool` not working on IE 10. ## 2021-01-16, version 6.0.4 - Make evaluation of offloaded functions a bit more secure by using `new Function` instead of `eval`. Thanks @tjenkinson. ## 2020-10-28, version 6.0.3 - Fixes and more robustness in terminating workers. Thanks @boneskull. ## 2020-10-03, version 6.0.2 - Fix #32, #175: the promise returned by `Pool.terminate()` now waits until subprocesses are dead before resolving. Thanks @boneskull. ## 2020-09-23, version 6.0.1 - Removed examples from the npm package. Thanks @madbence. ## 2020-05-13, version 6.0.0 BREAKING CHANGE: the library entry points are changed and new source maps are added. This may have impact on your project depending on your setup. - Created separate library entry points in package.json for node.js and browser. Thanks @boneskull. - Generated source maps for both minified and non-minified bundles. - Removed deprecation warnings for `options.nodeWorker` (renamed to `options.workerType`) and `pool.clear()` (renamed to `pool.terminate()`). ## 2019-12-31, version 5.0.4 - Fixed #121: `isMainThread` not working when using `worker_threads`. - Drop official support for node.js 8 (end of life). ## 2019-12-23, version 5.0.3 - Fixed library not working in the browser. See #106. ## 2019-11-06, version 5.0.2 - Fixed environment detection in browser. See #106. Thanks @acgrid. ## 2019-10-13, version 5.0.1 - Fixed #96: WorkerPool not cancelling any pending tasks on termination. ## 2019-08-25, version 5.0.0 - Deprecated option `nodeWorker` and created a new, more extensive option `workerType` giving full control over the selected type of worker. Added new option `'web'` to enforce use a Web Worker. See #85, #74. - In a node.js environment, the default `workerType` is changed from `'process'` to `'thread'`. See #85, #50. - Improved detection of environment (`browser` or `node`), fixing wrong detection in a Jest test environment. See #85. ## 2019-08-21, version 4.0.0 - Pass argument `--max-old-space-size` to child processes. Thanks @patte. - Removed redundant dependencies, upgraded all devDependencies. - Fixed Webpack issues of missing modules `child_process` and `worker_threads`. See #43. - Bundled library changed due to the upgrade to Webpack 4. This could possibly lead to breaking changes. - Implemented new option `maxQueueSize`. Thanks @colomboe. - Fixed exiting workers when the parent process is killed. Thanks @RogerKang. - Fixed #81: Option `minWorkers: 'max'` not using the configured `maxWorkers`. - Fixed not passing `nodeWorker` to workers initialized when creating a pool. Thanks @spacelan. - Internal restructure of the code: moved from `lib` to `src`. ## 2019-03-12, version 3.1.2 - Improved error message when a node.js worker unexpectedly exits (see #58). Thanks @stefanpenner. - Allocate debug ports safely, this fixes an issue cause workers to exit unexpectedly if more then one worker pool is active, and the process is started with a debugger (`node debug` or `node --inspect`). Thanks @stefanpenner. ## 2019-02-25, version 3.1.1 - Fix option `nodeWorker: 'auto'` not using worker threads when available. Thanks @stefanpenner. ## 2019-02-17, version 3.1.0 - Implemented support for using `worker_threads` in Node.js, via the new option `nodeWorker: 'thread'`. Thanks @stefanpenner. ## 2018-12-11, version 3.0.0 - Enable usage in ES6 Webpack projects. - Dropped support for AMD module system. ## 2021-06-17, version 2.3.4 - Backport fix for Node.js 16, see #309. Thanks @mansona. ## 2018-09-12, version 2.3.3 - Fixed space in license field in `package.json`. Thanks @sagotsky. ## 2018-09-08, version 2.3.2 - Add licence field to `package.json`. Thanks @greyd. ## 2018-07-24, version 2.3.1 - Fixed bug where tasks that are cancelled in a Pool's queue causes following tasks to not run. Thanks @greemo. ## 2017-09-30, version 2.3.0 - New method `Pool.terminate(force, timeout)` which will replace `Pool.clear(force)`. Thanks @jimsugg. - Fixed issue with never terminating zombie child processes. Thanks @jimsugg. ## 2017-08-20, version 2.2.4 - Fixed a debug issue: look for `--inspect` within argument strings, instead of exact match. Thanks @jimsugg. ## 2017-08-19, version 2.2.3 - Updated all examples to neatly include `.catch(...)` callbacks. ## 2017-07-08, version 2.2.2 - Fixed #25: timer of a timeout starting when the task is created instead of when the task is started. Thanks @eclipsesk for input. ## 2017-05-07, version 2.2.1 - Fixed #2 and #19: support for debugging child processes. Thanks @tptee. ## 2016-11-26, version 2.2.0 - Implemented #18: method `pool.stats()`. ## 2016-10-11, version 2.1.0 - Implemented support for registering the workers methods asynchronously. This enables asynchronous initialization of workers, for example when using AMD modules. Thanks @natlibfi-arlehiko. - Implemented environment variables `platform`, `isMainThread`, and `cpus`. Thanks @natlibfi-arlehiko. - Implemented option `minWorkers`. Thanks @sergei202. ## 2016-09-18, version 2.0.0 - Replaced conversion of Error-objecting using serializerr to custom implementation to prevent issues with serializing/deserializing functions. This conversion implementation loses the prototype object which means that e.g. 'TypeError' will become just 'Error' in the main code. See #8. Thanks @natlibfi-arlehiko. ## 2016-09-12, version 1.3.1 - Fix for a bug in PhantomJS (see #7). Thanks @natlibfi-arlehiko. ## 2016-08-21, version 1.3.0 - Determine `maxWorkers` as the number of CPU's minus one in browsers too. See #6. ## 2016-06-25, version 1.2.1 - Fixed #5 error when loading via AMD or bundling using Webpack. ## 2016-05-22, version 1.2.0 - Implemented serializing errors with stacktrace. Thanks @mujx. ## 2016-01-25, version 1.1.0 - Added an error message when wrongly calling `pool.proxy`. - Fixed function `worker.pool` not accepting both a script and options. See #1. Thanks @freund17. ## 2014-05-29, version 1.0.0 - Merged function `Pool.run` into `Pool.exec`, simplifying the API. ## 2014-05-14, version 0.2.0 - Implemented support for cancelling running tasks. - Implemented support for cancelling running tasks after a timeout. ## 2014-05-07, version 0.1.0 - Implemented support for both node.js and the browser. - Implemented offloading functions. - Implemented worker proxy. - Added docs and examples. ## 2014-05-02, version 0.0.1 - Module name registered at npm.