Typescript Error: Type 'any' is not a constructor function type
<p>I am currently trying out Angular 2 in combination with Ionic 2 so I am a bit new to TypeScript. Basically I was implementing a RESTService and I wanted to make the Rest Class abstract.</p>

<pre><code>export abstract class RESTService{

   mHttp: Http;
   mParameters: Parameter[];
   mURL: string;

   constructor (private http: Http, private parameters: Parameter[]){
       this.mHttp = http;
       this.mParameters = parameters;
   }

   // URL of the Rest Service
   abstract getURL() : string;

   // Convert or handle the Response
   handleResponse(rawResponse: Response){
       let body = rawResponse.json();
       return body.data || { };
   }

   // Handle an error 
   abstract handleError(error: any);

   // Do the rest call
   makeCall(): Observable&lt;any&gt; {
       return this.mHttp.get(this.mURL).map(this.handleResponse).catch(this.handleError);
   }}
</code></pre>

<p>And here is the class which extends from the RESTService:</p>

<pre><code>export class RESTServiceJourney extends RESTService{

   constructor(http:Http, parameters:Parameter[]){
       super(http, parameters);
   }

   // URL of the Rest Service
   getURL() : string {
        return "";
   }

   // Convert or handle the Response
   private handleResponse(rawResponse: Response){
       return "";
   }

   // Handle an error 
   private handleError(error: any){
       return "";
   }}
</code></pre>

<p>But I always get an <strong><em>Type 'any' is not a constructor function type</em></strong> error at the line "<strong><em>export class RESTServiceJourney extends RESTService</em></strong>". I searched through Google and Stackoverflow and do not know what kind of error this is. (I found one on Stackoverflow, but that one has problem with the version.)</p>

<p>Thanks in Advance!</p>