In my case the error occurred only during e2e tests. It was caused by throwError in my AuthenticationInterceptor.

I imported it from a wrong source because I used WebStorm's import feature. I am using RxJS 6.2.

Wrong:

import { throwError } from 'rxjs/internal/observable/throwError';

Correct:

import { throwError } from 'rxjs';

Here the full code of the interceptor:

import { Injectable } from '@angular/core';
import { HttpErrorResponse, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

@Injectable()
export class AuthenticationInterceptor implements HttpInterceptor {

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const reqWithCredentials = req.clone({withCredentials: true});
    return next.handle(reqWithCredentials)
     .pipe(
        catchError(error => {
          if (error.status === 401 || error.status === 403) {
            // handle error
          }
          return throwError(error);
        })
     );
  }
}

In your example code, you have your map operator receiving two callbacks, when it should only be receiving one. You can move your error handling code to your catch callback.

checkLogin():Observable<boolean>{
    return this.service.getData()
                       .map(response => {  
                          this.data = response;                            
                          this.checkservice=true;
                          return true;
                       })
                       .catch(error => {
                          this.router.navigate(['newpage']);
                          console.log(error);
                          return Observable.throw(error);
                       })
   }

You'll need to also import the catch and throw operators.

import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';

EDIT: Note that by returning Observable.throwin your catch handler, you won't actually capture the error - it will still surface to the console.

If your function is expecting to return a boolean, just do this:

1. Import:

import { of, Observable } from 'rxjs';
import { map, catchError } from 'rxjs/operators';

2. Then

checkLogin(): Observable<boolean> {
  return this.service.getData()
    .pipe(
      map(response => {
        this.data = response;
        this.checkservice = true;
        return true;
      }),
      catchError(error => {
        this.router.navigate(['newpage']);
        console.log(error);
        return of(false);
      })
)}