Property 'error' does not exist on type '"" | Promise<any>'

Question

I'm trying to add some error handling to a service, following the Angular guide.

Relevant snippet:

private handleError (error: Response | any) {
  // In a real world app, you might use a remote logging infrastructure
  let errMsg: string;
  if (error instanceof Response) {
    const body = error.json() || '';
    const err = body.error || JSON.stringify(body);
    errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
  } else {
    errMsg = error.message ? error.message : error.toString();
  }
  console.error(errMsg);
  return Observable.throw(errMsg);
}

However, I'm getting a TypeScript error:

error TS2339: Property 'error' does not exist on type '"" | Promise<any>'. Property 'error' does not exist on type '""'.

I can understand why it's happening-- error.json() returns a Promise<any> and then the subsequent line with body.error wouldn't work because there is no error property. However, it seems like it should expect a JSON object to be returned from .json(). Why is that, and what am I missing that the Angular guide isn't?

Answer 1

Same thing just happened to me. This happens when you fail to import the Response object.

import { Response } from '@angular/http';