Angular 2, best practice to load data from a server one time and share results to components [duplicate]

Answer 1

The right place is definitely a service. If you add this service as provider at one place only, one instance is shared with the whole application. If you add it to providers on each component, each component gets its own instance - which is what you want to avoid

bootstrap(AppComponent, [HTTP_PROVIDERS, MyService]);

@Component({
  selector: 'some-comp',
  providers: [/* don't add MyService here !! */]})
class MyComponent {}