switchMap(
  () =>
    new Observable(observer => {
      const abortController = new AbortController()
      fetch(url, { signal: abortController.signal })
        .then(res => {
          observer.next(res)
          observer.complete()
        })
        .catch(err => observer.error(err))
      return () => abortController.abort()
    })
)

modalRef.result
  .then(idForDeletion => {
    this.itemsRepository.delete(idForDeletion)
      .pipe(catchError(this.handleFailure.bind(this)))
      .subscribe(() => {
        this.reload();
        this.notificationsService.success();
      });
  })
  .catch(this.reload.bind(this));

from(modalRef.result)
  .pipe(switchMap(this.itemsRepository.delete),
    catchError(this.reload.bind(this))
  )
  .subscribe(() => {
    this.reload();
    this.notificationsService.success();
  });