Nickel Palladium Manganese

    @builder.io/worker-loader

    2.0.1 • Public • Published

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    worker-loader

    worker loader module for webpack

    Requirements

    This module requires a minimum of Node v6.9.0 and Webpack v4.0.0.

    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: {
        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
    {
      loader: 'worker-loader'
      options: { fallback: false }
    }

    inline

    Type: Boolean Default: false

    You can also inline the worker as a BLOB with the inline parameter

    // webpack.config.js
    {
      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
    {
      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
    {
      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
    {
      loader: 'worker-loader'
      options: { publicPath: '/scripts/workers/' }
    }

    crossOrigin

    Type: Boolean Default: false

    This is useful if you want to host your javascript and worker code on a CDN and only makes sense if you have configured a publicPath globally in webpack or local to this loader that is on a different domain than your html is served.

    // **webpack.config.js**
    {
      loader: 'worker-loader'
      options: {
        publicPath: 'https://cdn.mysite.fast/',
        crossOrigin: true,
      }
    }

    Examples

    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 ES2015 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/custom.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
    {
      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
    {
      loader: 'worker-loader'
      options: { publicPath: '/workers/' }
    }

    Contributing

    Please take a moment to read our contributing guidelines if you haven't yet done so.

    CONTRIBUTING

    License

    MIT

    Keywords

    Install

    npm i @builder.io/worker-loader

    DownloadsWeekly Downloads

    111

    Version

    2.0.1

    License

    MIT

    Unpacked Size

    18.7 kB

    Total Files

    10

    Last publish

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