How to use the @sanity/observable function in @sanity/observable

export function timer(initialDelay, period) {
  return new Observable(observer => {
    let n = 0
    let intervalId = -1

    const timeoutId = setTimeout(() => {
      emitNext()
      if (period !== undefined) {
        intervalId = setInterval(emitNext, period)
      }
    }, initialDelay)

    function emitNext() {
      observer.next(n++)
    }
    return function dispose() {
      clearTimeout(timeoutId)
      clearInterval(intervalId)

function listen(id) {
  return new Observable(observer => {
    observer.next({type: 'welcome', documentId: id})
    return globalListener
      .filter(event => event.documentId === id)
      .debounceTime(2000)
      .subscribe(observer)
  })
}

import Observable from '@sanity/observable'

function getWindowDimensions() {
  return {
    height: window.innerHeight,
    width: window.innerWidth
  }
}

const EVENTS = ['scroll', 'resize']

const scrollObserver = new Observable(observer => {
  const listener = () => observer.next(getWindowDimensions())
  EVENTS.forEach(eventType => {
    document.body.addEventListener(eventType, listener, true)
  })

  return () => {
    EVENTS.forEach(eventType => {
      document.body.removeEventListener(eventType, listener, true)
    })
  }
})
  .debounceTime(100)
  .share()

export default new Observable(observer => {
  observer.next(getWindowDimensions())