Just here for future reference, a (draft) inline web worker class.

inline-web-worker.ts

/**
 * Abstract class used to create and spwan inline workers.
 *
 * Workers can be created by extending the WebWorker class and creating
 * your own implementation of 'perform()'. The extended class can then
 * be used to spawn the new worker and communicate with it.
 *
 * @example
 *
 * class StorageWorker extends WebWorker {
 *    protected perform(this: never) {
 *        self.onmessage = (message) => {
 *            localStorage.setItem(message.data.key, message.data.data);
 *        }
 *    }
 * }
 *
 * const worker = new StorageWorker();
 *
 * worker.execute();
 * worker.sendMessage({
 *      key: 'storageKey',
 *      data: {some: 'data'}
 * });
 */

export abstract class WebWorker<T = any> {

    private worker: Worker | undefined;

    constructor(readonly config?: T) { }

    /**
     * The code executed by the WebWorker. Note that this can't communicate with
     * the class context, since it runs in the WebWorker context.
     *
     * Use 'self' to refer to ServiceWorkerContainer
     */
    protected abstract perform(this: never, config?: T);

    /**
     * Creates a new worker instance for the given class and executes it.
     * Further communication can be done with {@see sendMessage}
     */
    execute() {
        this.worker = this.createWorker();
    }

    /**
     * Stop the current worker
     */
    stop() {
        if (!this.worker) {
            throw new Error('Missing active worker. Make sure you call `execute()` first.');
        }

        this.worker.terminate();
    }

    /**
     * Send messages to the active worker. This does not take care
     * of any serialization.
     *
     * @param data
     */
    sendMessage(data: any) {
        if (!this.worker) {
            throw new Error('Missing active worker. Make sure you call `execute()` first.');
        }
        this.worker.postMessage(data);
    }

    /**
     * Create a new inline web worker
     */
    private createWorker(): Worker {
        const blob = new Blob([`(${this.perform.toString()})(${JSON.stringify(this.config || {})});`], { type: 'text/javascript' });
        const url = URL.createObjectURL(blob);
        return new Worker(url);
    }
}