https://github.com/developit/jsdom-worker

👷‍♀️ Use Web Workers in Jest / JSDOM 🌈
https://github.com/developit/jsdom-worker

jest jest-environment jest-plugin jsdom web-worker webworker

Last synced: 4 days ago
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👷‍♀️ Use Web Workers in Jest / JSDOM 🌈

• Host: GitHub
• URL: https://github.com/developit/jsdom-worker
• Owner: developit
• Created: 2018-01-31T20:44:22.000Z (almost 7 years ago)
• Default Branch: main
• Last Pushed: 2023-04-06T08:37:17.000Z (over 1 year ago)
• Last Synced: 2024-12-23T06:06:46.856Z (11 days ago)
• Topics: jest, jest-environment, jest-plugin, jsdom, web-worker, webworker
• Language: JavaScript
• Homepage: https://npm.im/jsdom-worker
• Size: 199 KB
• Stars: 287
• Watchers: 8
• Forks: 20
• Open Issues: 12
• Metadata Files:
  • Readme: README.md

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README

        


  



# jsdom-worker

> _Lets you use Web Workers in Jest!_

This is an experimental implementation of the Web Worker API (specifically Dedicated Worker) for JSDOM.

It does not currently do any real threading, rather it implements the `Worker` interface but all work is done in the current thread. `jsdom-worker` runs wherever JSDOM runs, and does not require Node.

It supports both "inline" _(created via Blob)_ and standard _(loaded via URL)_ workers.

> **Hot Take:** this module likely works in the browser, where it could act as a simple inline worker "poorlyfill".

 

## Why?

Jest uses a JSDOM environment by default, which means it doesn't support Workers. This means it is impossible to test code that requires both NodeJS functionality _and_ Web Workers. `jsdom-worker` implements enough of the Worker spec that it is now possible to do so.

## Installation

`npm i jsdom-worker`

## Example

```js

import 'jsdom-global/register';

import 'jsdom-worker';

let code = `onmessage = e => postMessage(e.data*2)`;

let worker = new Worker(URL.createObjectURL(new Blob([code])));

worker.onmessage = console.log;

worker.postMessage(5); // 10

```

## Usage with Jest

For single tests, simply add `import 'jsdom-worker'` to your module.

Otherwise, add it via the [setupFiles](https://facebook.github.io/jest/docs/en/configuration.html#setupfiles-array) Jest config option:

```js

{

  "setupFiles": [

    "jsdom-worker"

  ]

}

```

## License

[MIT License](https://oss.ninja/mit/developit)