settings.ts

class SettingsService {
    private _instance;

    get() {
        return this._instance
    }

    set(settings) {
        this._instance = settings;
    }
}

const settingsService = new SettingsService();

abstract class App {
    constructor() {
        const settings = this.getSettings();

        settingsService.set(settings);
    }

    getSettings(): BaseSettings;
}


class BaseSettings {

}

class WorkerSettings {

}


class RequesterSettings {

}

class WorkerApp extends App {
    getSettings() {
        return new WorkerSettings();
    }
}

class RequesterApp extends App {
    getSettings() {
        return new RequesterSettings();
    }
}


new WorkerApp();