如何将公共依赖项注入其他Angular2 @Injectable类？

Question

I have created a component base in TypeScript which I would like to share many services.

export abstract class ComponentBase<T> {
  constructor(protected http:Http, protected router: Router, protected route: ActivatedRoute, protected params: Params) {
  }
}

The problem is that I have multiple nested types and so whenever I have to derive any level down the hierarchy. Each derived type would look something like this passing down the base's injected parameters.

import { Http } from '@angular/http';
import { Router, ActivatedRoute, Params } from '@angular/router';
export  class SomeDerivedType extends ComponentBase<SomeType> {
  constructor(protected http: Http, protected router: Router, protected route: ActivatedRoute, protected params: Params) {
    super(http, router, route, params);
  }
}

I have to chain my constructors to satisfy the base class's constructor parameters. This is quite annoying overhead. Therefore, I have created a Services class to hold all the encapsulated dependencies.

import { Injectable } from '@angular/core';
import { Router, ActivatedRoute, Params } from '@angular/router';
import { Http } from "@angular/http";

@Injectable()
export class Services {
  constructor(public http:Http, public router: Router,  public route: ActivatedRoute, public params: Params) {
  }
}

I thought I should be able to just inject this services class into the components as follows.

import { Services } from './services'
export class SomeDerivedType extends ComponentBase<any> {
  constructor(protected services: Services) {
    super(services);
  }
}

And the component base now looks as follows:

import { Services } from './services';
import { Http } from '@angular/http';
import { Router, ActivatedRoute, Params } from '@angular/router';

export abstract class ComponentBase<T> {
  http: Http;
  router: Router;
  route: ActivatedRoute;
  params: Params;
  constructor(protected services: Services ) {
    this.http = services.http;
    this.route = services.route;
    this.router = services.router;
    this.params = services.params;
  }
}

This unfortunately is not working for me, instead I get the following error:

(index):63 Error: Error: Can't resolve all parameters for Services: ([object Object], [object Object], [object Object], ?).

So, naturally my question is , "Is there a way to have the dependent services (ie. http,router,route, and params services) injected into my services class?"

Answer 1

Well, as it turns out I just missed something about angular that wasn't clear to me. I have only been using it for a little while. The problem was actually simple. Params is not a service.

(index):63 Error: Error: Can't resolve all parameters for Services: ([object Object], [object Object], [object Object], ?).

The message threw me off because it said can't resolve all. I misinterpreted it, as it was really telling me that one of the parameters was not being resolved. In my case protected params : Params.

This code now works beautifully just as I hoped it would by removing the params item.