How to throw an observable error manually?

Solution 1:

if (response.success == 0) {
   throw Observable.throw(response);  
 }

Edit for rxjs 6:

if (response.success == 0) {
   throw throwError(response);  
 }

rxjs 6

import { throwError } from 'rxjs';

if (response.success == 0) {
  return throwError(response);  
}

rxjs 5

import { ErrorObservable } from 'rxjs/observable/ErrorObservable';

if (response.success == 0) {
  return new ErrorObservable(response);  
}

What you return with ErrorObservable is up to you

with rxjs 6

import { throwError } from 'rxjs';
throwError('hello');