How do I debug a “[object ErrorEvent] thrown” error in my Karma/Jasmine tests?

Question

I have several failing tests that only output [object ErrorEvent] thrown. I don\'t see anything in the console that helps me pinpoint the offending code. Is t

Answer 1

In my case the problem was with the service, as one of the object wil be undefined during tests running.

Service code sample was something like below access to dom,

  const elem = this.document.querySelector(element) as HTMLElement;
  elem.scrollIntoView({param1: ''});

The specs referring to this service were failing with the error '[object ErrorEvent] thrown'.

I mocked my service object inside all the specs which were referring to this and the issue got resolved.

Mock service

class MockService {
serviceMethod(div) : void {
  testElement = document.querySelector('div') as HTMLElement;
  return testElement;
  } 
}

And use this mock service object in providers as below,

beforeEach(async(() => {

TestBed.configureTestingModule({
  declarations: [Component],
  providers: [
     { provide: Service, useClass: MockService },
    ],
})
  .compileComponents();
}));