How to create an Observable from static data similar to http one in Angular?

As of July 2018 and the release of RxJS 6, the new way to get an Observable from a value is to import the of operator like so:

import { of } from 'rxjs';

and then create the observable from the value, like so:

of(someValue);

Note, that you used to have to do Observable.of(someValue) like in the currently accepted answer. There is a good article on the other RxJS 6 changes here.

Perhaps you could try to use the of method of the Observable class:

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/of';

public fetchModel(uuid: string = undefined): Observable<string> {
  if(!uuid) {
    return Observable.of(new TestModel()).map(o => JSON.stringify(o));
  }
  else {
    return this.http.get("http://localhost:8080/myapp/api/model/" + uuid)
            .map(res => res.text());
  }
}