Registry / testing / workerloader-jest-transformer

workerloader-jest-transformer

library0.1.0jsnpmunverified

A Jest transformer for Webpack worker-loader that enables testing Web Workers with Jest. This package transforms worker files (matched by regex) into mock workers that emulate the Worker API, allowing tests to run in Node.js without a browser environment. Inspired by jsdom-worker. Current version 0.1.0 is unstable and experimental; the project is seeking maintainers. Key differentiators: specifically designed for worker-loader, uses a lightweight mock with terminate/close semantics.

testing

npm install workerloader-jest-transformer

github ↗package ↗

INSTALL

IMPORT

SIG · WORKERLOADER-JEST-

workerloader-jest-transformer

testingjavascriptv0.1.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–223 runs

build_error

glibc

node 18–223 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

workerloader-jest-transformer

✓ /* No import; configure in jest config */

✗ const transformer = require('workerloader-jest-transformer'); // not used directly

This package is a Jest transformer, not a library you import. Configure it in your Jest transform map.

Shows how to configure jest transform and test a web worker that doubles a number.

// jest.config.js module.exports = { transform: { '^.+\\.worker.[t|j]sx?$': 'workerloader-jest-transformer' } }; // src/example.worker.js self.onmessage = function(e) { postMessage(e.data * 2); }; // __tests__/example.test.js const Worker = require('worker-loader!../src/example.worker.js'); test('worker doubles number', (done) => { const worker = new Worker(); worker.onmessage = (e) => { expect(e.data).toBe(4); done(); }; worker.postMessage(2); });

Debug

Known issues

breakingHigh experimental state: not stable, lacking tests, and may change API without notice.

fix

Consider alternatives like jsdom-worker or manual worker mocking for production.

affects: 0.x

deprecatedPackage maintainers wanted; project may be abandoned if no maintainers step up.

fix

Fork the repository or migrate to maintained alternatives.

affects: *

gotchaRequires worker-loader in webpack config for the original code, but the transformer only works with Jest transform.

fix

Ensure your webpack config also includes worker-loader for non-test builds.

affects: *

Errors

Common errors & fixes

Cannot find module 'workerloader-jest-transformer'

Package not installed or Jest transform path misspelled.

fix

npm install --save-dev workerloader-jest-transformer

Jest encountered an unexpected token - This usually means that you are trying to import a file which Jest cannot parse

Worker file not matching the transform regex or transform not configured.

fix

Ensure transform regex in jest config matches your worker files, e.g., '^.+\\.worker.[t|j]sx?$'

Upgrade

Version history

0.1.0latest on npm

Audit

Dependencies

@babel/corerequiredPeer dependency required for transforming worker files with Babel

Agent activity

15 hits · last 30 days

node

Resources

githubhttps://github.com/astagi/workerloader-jest-transformer ↗

packagehttps://www.npmjs.com/package/workerloader-jest-transformer ↗