title: Inject non-singleton service into non-singleton service in Angular
body: <p>What would be the way to go if I wanted to inject a non-singleton service into another non-singleton service in Angular?</p>
  <p>Let's say I have a <code>ComponentA</code> which uses a <code>ServiceA</code> like this</p>
  <pre><code>@component({
    selector: &quot;componentA&quot;,
    providers: [ServiceA]
  })
  export class ComponentA {
    constructor(private serviceA: ServiceA) {}
  }
  </code></pre>
  <p>and now, <code>ServiceA</code> also depends on <code>ServiceB</code>, so I need to inject it</p>
  <pre><code>@Injectable()
  export class ServiceA {
     constructor(private serviceB: ServiceB) {}
  }
  </code></pre>
  <p>How/where would I declare my <code>ServiceB</code>? In the module? In that case would that be a singleton?</p>
  <p>If I add it to the providers in <code>ComponentA</code> it works fine, but then I need to know in <code>ComponentA</code> that <code>ServiceA</code> depends on <code>ServiceB</code>, which doesn't seem fine to me.</p>
  <p>Thanks!</p>