Angular 2 inject service into extended class(BaseRequestOptions)

Question

I have the following code that extends the BaseRequestOptions class:

import { Injectable } from \'@angular/core\';

@Injectable()
export class AppReq         


        

Answer 1

This is very similar to the question I answered here: Injected dependency is undefined when extending BaseRequestOptions

When defining your provider also define the dependencies needed, so the object in your providers definition would look like:

{
 provide: RequestOptions,
 useClass: AppRequestOptions,
 deps: [ServiceA]
}

Answer 2

There is an open bug for this: https://github.com/angular/angular/issues/9758.

Whereas the metadata for dependency injection is correctly set, the element isn't provided to the class instance at the constructor level.

@Injectable()
export class AppRequestOptions extends BaseRequestOptions {
  constructor(private serviceA:ServiceA) {       
    super();        
    console.log(Reflect.getMetadata('design:paramtypes', AppRequestOptions));
    console.log(Reflect.getMetadata('parameters', AppRequestOptions));
  }

  (...)
}

See this plunkr for more details: https://plnkr.co/edit/hcqAfsI7u88jbjScq6m3?p=preview.

Edit

It will work if you use the RequestOptions class instead of the BaseRequestOptions one:

@Injectable()
export class AppRequestOptions extends RequestOptions {
  constructor(private serviceA:ServiceA) {       
    super();        
  }   

  (...)
}

See this plunkr: https://plnkr.co/edit/laP04kqUCOR5qbFgo0iM?p=preview.