function identity(x) { return x; }

​

Rx.Observable.create(o => {

      console.log('subscribing');

      o.onError(new Error('always fails'));

  }).retryWhen(attempts => {

      return Rx.Observable.range(1, 3)

        .zip(attempts, identity)

        .flatMap(i => {

          console.log('delay retry by ' + i + ' second(s)');

          return Rx.Observable.timer(i * 1000);

      });

  }).subscribe();

​

// => subscribing

// => delay retry by 1 second(s)

// => subscribing

// => delay retry by 2 second(s)

// => subscribing

// => delay retry by 3 second(s)

// => subscribing