@johngw/stream/test/sinks/ForkableRecallStream.test.ts

Reactive programming tools using the WHATWG Streams API.

import { ForkableRecallStream } from '@johngw/stream/sinks/ForkableRecallStream'
import { fromCollection } from '@johngw/stream/sources/fromCollection'
import { write } from '@johngw/stream/sinks/write'

test('subscribing will always provide that last chunk', async () => {
  const forkable = new ForkableRecallStream()
  await fromCollection([1, 2, 3, 4, 5]).pipeTo(forkable)
  const fn1 = jest.fn()
  const fn2 = jest.fn()
  await forkable.fork().pipeTo(write(fn1))
  await forkable.fork().pipeTo(write(fn2))
  expect(fn1).toHaveBeenCalledTimes(1)
  expect(fn1).toHaveBeenCalledWith(5)
  expect(fn2).toHaveBeenCalledTimes(1)
  expect(fn2).toHaveBeenCalledWith(5)
})