Angular: what is the difference between declaring a service in a component and the boot process

Question

What is the difference between this:

bootstrap(AppComponent, [HeroService]);

And this:

@Component({
  selector: 'test',
  providers: [HeroService]
})

Answer 1

If you add it only to bootstrap(), you will get a singleton, if you add it to a component, you will get a new instance for each instance of the component. If you add it to both, it depends on where you enter it. Angular2 has a hierarchical DI. He is looking up for the provider, the first one returned is returned.

See also http://blog.thoughtram.io/angular/2015/05/18/dependency-injection-in-angular-2.html

Answer 2

HeroService bootstrap, HeroService - , .

providers .

Angular 2.

Answer 3

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