无法访问Angular 2中的儿童服务成员

Question

I create 2 services

export class BaseService {

  constructor() { }
}

And another service like

export class ChildService extends BaseService {

  constructor() { 
    super();
  }

  sayHello() { 
     alert("Hello");
  }

}

And i used it in component like

constructor(private child : ChildService) {
  this.child.sayHello(); // It will throw error that sayHello not available.
}

Answer 1

Your service should be Injectable:

@Injectable
export class BaseService {
...

And should be provided to module if it is still not:

@NgModule
...
providers: [BaseService]