Angular2 Beta dependency injection

Question

I have a NavBar Component which loads the QApi Service, the QApi Service loads the UserService, but I get the following error:

EXCEPTION: No provider for Use         


        

Answer 1

Add UserService to the component providers:

@Component({
    selector: 'nav-bar',
    template: `Test NavBar`,
    providers: [QApi, UserService] // <- add UserService here
})
export class NavBarComponent { /* ... */ }

Here are two good articles to better understand Angular2 Dependency Injection:

• blog.thoughtram.io: Dependency Injection in Angular2
• blog.thoughtram.io: Injecting services in services in Angular 2