@juanger/worker-loader
v2.0.1-beta.1
Published
worker loader module for webpack
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worker-loader
worker loader module for webpack
Getting Started
To begin, you'll need to install worker-loader
:
$ npm install worker-loader --save-dev
Inlined
App.js
import Worker from 'worker-loader!./Worker.js';
Config
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.worker\.js$/,
use: { loader: 'worker-loader' },
},
],
},
};
App.js
import Worker from './file.worker.js';
const worker = new Worker();
worker.postMessage({ a: 1 });
worker.onmessage = function (event) {};
worker.addEventListener('message', function (event) {});
And run webpack
via your preferred method.
Options
fallback
Type: Boolean
Default: false
Require a fallback for non-worker supporting environments.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.worker\.js$/,
use: { loader: 'worker-loader' },
options: { fallback: true },
},
],
},
};
inline
Type: Boolean
Default: false
You can also inline the worker as a BLOB with the inline
parameter.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.worker\.js$/,
use: { loader: 'worker-loader' },
options: { inline: true },
},
],
},
};
Note: Inline mode will also create chunks for browsers without support for inline workers, to disable this behavior just set fallback
parameter as false
.
webpack.config.js
module.exports = {
module: {
rules: [
{
loader: 'worker-loader',
options: { inline: true, fallback: false },
},
],
},
};
name
Type: String
Default: [hash].worker.js
To set a custom name for the output script, use the name
parameter.
The name may contain the string [hash]
, which will be replaced with a content dependent hash for caching purposes.
When using name
alone [hash]
is omitted.
webpack.config.js
module.exports = {
module: {
rules: [
{
loader: 'worker-loader',
options: { name: 'WorkerName.[hash].js' },
},
],
},
};
publicPath
Type: String
Default: null
Overrides the path from which worker scripts are downloaded. If not specified, the same public path used for other webpack assets is used.
webpack.config.js
module.exports = {
module: {
rules: [
{
loader: 'worker-loader',
options: { publicPath: '/scripts/workers/' },
},
],
},
};
workerType
Type: string
Default: Worker
Set the worker type. Defaults to Worker
. Supports ServiceWorker
, SharedWorker
.
Examples
Basic
The worker file can import dependencies just like any other file:
Worker.js
const _ = require('lodash');
const obj = { foo: 'foo' };
_.has(obj, 'foo');
// Post data to parent thread
self.postMessage({ foo: 'foo' });
// Respond to message from parent thread
self.addEventListener('message', (event) => console.log(event));
Integrating with ES Modules
Note: You can even use ES2015 Modules if you have the babel-loader
configured.
Worker.js
import _ from 'lodash';
const obj = { foo: 'foo' };
_.has(obj, 'foo');
// Post data to parent thread
self.postMessage({ foo: 'foo' });
// Respond to message from parent thread
self.addEventListener('message', (event) => console.log(event));
Integrating with TypeScript
To integrate with TypeScript, you will need to define a custom module for the exports of your worker
typings/worker-loader.d.ts
declare module 'worker-loader!*' {
class WebpackWorker extends Worker {
constructor();
}
export default WebpackWorker;
}
Worker.ts
const ctx: Worker = self as any;
// Post data to parent thread
ctx.postMessage({ foo: 'foo' });
// Respond to message from parent thread
ctx.addEventListener('message', (event) => console.log(event));
App.ts
import Worker from 'worker-loader!./Worker';
const worker = new Worker();
worker.postMessage({ a: 1 });
worker.onmessage = (event) => {};
worker.addEventListener('message', (event) => {});
Cross-Origin Policy
WebWorkers
are restricted by a same-origin policy, so if your webpack
assets are not being served from the same origin as your application, their download may be blocked by your browser.
This scenario can commonly occur if you are hosting your assets under a CDN domain.
Even downloads from the webpack-dev-server
could be blocked.
There are two workarounds:
Firstly, you can inline the worker as a blob instead of downloading it as an external script via the inline
parameter
App.js
import Worker from './file.worker.js';
webpack.config.js
module.exports = {
module: {
rules: [
{
loader: 'worker-loader',
options: { inline: true },
},
],
},
};
Secondly, you may override the base download URL for your worker script via the publicPath
option
App.js
// This will cause the worker to be downloaded from `/workers/file.worker.js`
import Worker from './file.worker.js';
webpack.config.js
module.exports = {
module: {
rules: [
{
loader: 'worker-loader',
options: { publicPath: '/workers/' },
},
],
},
};
Contributing
Please take a moment to read our contributing guidelines if you haven't yet done so.