To begin, you'll need to install sharedworker-loader $ npm install --save-dev [email protected]

With the sharedworker-loader plug-in, you don't have to add code split config in webpack to split your worker script separately. If you are also using typescript, the only rules you needed to add are

module: {
        rules: [
            // all files with a '.ts' or '.tsx' extension will be handled by 'ts-loader'
            {
                test: /\.tsx?$/,
                use: {
                    loader: "ts-loader"
                }
            },
            {
                test: /\.worker\.js$/,
                use: { loader: 'sharedworker-loader' }
            }
            
        ]
}

So how the script gets split out without code spliting?

The magic lays in the require statement

import SharedWorker = require("sharedworker-loader?name=worker.js!./worker/mainworker");

The require statement contains 3 parts: loader + script bundled name + entry point.

• loader: see if sharedworker-loader dependency is added
• script bundled name: the name of the bundled worker script
• entry point: the entry point for worker.

Similar what worker-loader mentioned in their readme, you need to add a custom.d.ts for typescript to resolve the type of the imported worker module. In order to do you'll need to

• npm install --save-dev @types/sharedworker
• create a typing definition for the module you imported

declare module "sharedworker-loader*" {
    class WebpackSharedWorker extends SharedWorker {
        constructor();
    }

    export = WebpackSharedWorker;
}

Voilà, when do npm run build, you'll see the worker script get splited out separately.

Some of you might have come across this PR https://github.com/webpack-contrib/worker-loader/pull/98/files. The change about creating sharedworker actually only merged into their feature branch feat-mode So that's a no go for me.