How to use factory provider?

I need to inject a service into another service in an Angular 2 application.

After reading the docs I deduced, that the best approach is to use a Factory Provider. However, two questions have arisen:

1) The docs recommend the creation of a HeroServiceProvider class with two "code segments":

let heroServiceFactory = (logger: Logger, userService: UserService) => {
return new HeroService(logger, userService.user.isAuthorized);
};

export let heroServiceProvider =
{ provide: HeroService,
useFactory: heroServiceFactory,
deps: [Logger, UserService]
};


My question is how should the class generally look like? Where should one add the above code segments?

2) How should/could one use this factory? I see, it should be imported as:

import { heroServiceProvider } from './hero.service.provider';

@Component({
selector: 'my-selector',
template: `
`,
providers: [heroServiceProvider]
})


How could then the desired parametrized service retrieved and accessed?

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