• Install
• Requirements
• Usage
• How it works
• Modifications to node worker_threads
• Modifictaion to browser WebWorkers
• Options
  • plugins
  • type

Install

npm i -D rollup-plugin-worker-factory

Requirements

• browsers with web worker support (tested in ie 11)
• nodejs >= 10 when node is run with --experimental-workers
• natively in nodejs >= 12 without any arguments to node

Usage

include rollup-plugin-worker-factory in your rollup plugins array for a build:

const worker = require('rollup-plugin-worker-factory');

...
plugins: [
  worker()
]
...

When you want to include a worker in your code prefix the file with worker!:

import SomeWorker from "worker!./src/some-worker.js";

Your worker should run without exporting any code and use the global self variable to interact with the worker API. worker_threads.parentPort for node has been slightly modified so that their API more closely matches web workers in the browser and will also be available on the global self.

const someDependency = require('../some-dep');
const whoKnows = require('who-knows');

self.addEventListener('message', function(e) {
  const foo = someDependency(e);

  self.postMessage(whoKnows(foo));
});

How it works

1. We use rollup to rollup all dependencies for your web worker file into a bundle.
2. We wrap that rollup in a function so that it can be minified and included normally in your code without doing anything.
3. We return a web worker constructor for your function that will run in the web worker with slight modifications to unify the API (nothing that you, the user should have to worky about).

Modifications to node worker_threads

• We mirror on to addEventListener on worker objects
• We mirror off to removeEventListener on worker objects
• We wrap postMessage so that the message sent is included as a value for a data key on an object as this is how the browser works with postMessage.

Modifictaion to browser WebWorkers

• We automagically create a blob url of your code to run in the worker that will be revoked on worker terminate
• We mirror addEventListener to on on worker objects
• We mirror removeEventListener to on on worker objects
• We add the created blob url to the worker as an objURL property

Options

plugins

An array of rollup plugins to bundle the web workers with, you will probably want:

type

Default: 'universal'

The type of factory to build, can be 'node', 'mock', 'browser', or 'universal'.

• browser will only work in the browser

• node will only work in node

• mock will work everywhere but runs on the same thread

• universal will work on the browser or node depending on available apis

• @rollup/plugin-node-resolve

• @rollup/plugin-json

• @rollup/plugin-commonjs