title: override angular class variable in a service import
body: <p>I have a angualar4 RestService exported, I need to override baseUrl to places where I import it.</p>
  
  <pre><code>   @Injectable()
      export class RestService {
  
        // needs to be more dynamic this should be changed later to use http or https
        // depending on if it is available
        private baseUrl: string = "/api/v1.0/";
  
  
  
      }
  </code></pre>
  
  <p>========importing it in Different file and using it in constructor=========</p>
  
  <pre><code>import {RestService} from '../../../../services/';
  
  constructor(protected rest: RestService) {}
  // I would like to change baseUrl to "/api/v2.0/" as needed.
  </code></pre>