var counter = 0;

var respond = 4

var observable = Rx.Observable

    .create(observable => {

      if(counter == respond) {

        observable.onNext('response');

        observable.onCompleted();                  

      } else {

        observable.onError('error');

        counter++; 

      }

    })

    .retry(respond + 1);

​

observable.subscribe(value => console.log(value),

                     error => console.log(error));

​