text: import $$observable from 'symbol-observable';
  import Rx from 'rx';
  
  const config = {
    fromESObservable: observable =>
      Rx.Observable.create(observer => {
        const { unsubscribe } = observable.subscribe({
          next: val => observer.onNext(val),
          error: error => observer.onError(error),
          complete: () => observer.onCompleted(),
        });
        return unsubscribe;
      }),
    toESObservable: rxObservable => ({
      subscribe: observer => {
        const subscription = rxObservable.subscribe(
          val => observer.next(val),
          error => observer.error(error),
          () => observer.complete()
        );
        return { unsubscribe: () => subscription.dispose() };
      },
      [$$observable]() {
        return this;
      },
    }),
  };
  
  export default config;
  