flattenSequentially problem

bug.js

const xs = require('xstream').default

const flattenSequentially = require('xstream/extra/flattenSequentially').default

const createTestObservable = item => {
  return xs.create({
    start: function(listener) {
      setTimeout(() => {
        listener.next(item)
        listener.complete()
      }, 1000)
    },
    stop: () => {}
  })
}

xs.fromArray([1, 2])
  .map(createTestObservable)
  .compose(flattenSequentially)
  .subscribe({
    next: console.log,
    error: console.error
  })

xs.fromArray([3])
  .map(createTestObservable)
  .compose(flattenSequentially)
  .subscribe({
    next: console.log,
    error: console.error
  })