import isObsv from 'is-observable'

interface Subscription {
  /* Cancels the subscription */
  unsubscribe (): void

  /** A boolean value indicating whether the subscription is closed */
  closed: boolean
}

/** Stripped down Observable interface */
interface Observable {
  subscribe (
    onNext: Function,
    onError?: Function,
    onComplete?: Function
  ): Subscription
}

/** Returns true if the value passed in is an Observable */
function isObservable (x: any): x is Observable {
  return isObsv(x)
}

export {
  Observable,
  Subscription,
  isObservable
}