@johngw/stream/test/transformers/bufferCount.test.ts

Reactive programming tools using the WHATWG Streams API.

import { fromTimeline } from '@johngw/stream-jest'
import { bufferCount } from '@johngw/stream/transformers/bufferCount'

test('bufferCount in 2s', async () => {
  await expect(
    fromTimeline(`
    -1-2---3-4---5-6---7-8-----|
    `).pipeThrough(bufferCount(2))
  ).toMatchTimeline(`
    ---[1,2]-[3,4]-[5,6]-[7,8]-
  `)
})

test('queues whatever remains after stream has closed', async () => {
  await expect(
    fromTimeline(`
    -1-2-3-4-5-------6-7-8-|
    `).pipeThrough(bufferCount(5))
  ).toMatchTimeline(`
    ---------[1,2,3,4,5]---[6,7,8]-
  `)
})

test('infinit numbers will error', () => {
  expect(() => bufferCount(Infinity)).toThrow(
    'bufferCount() cannot be used with an infinite number.'
  )
})

test('floating points will error', () => {
  expect(() => bufferCount(1.1)).toThrow(
    'bufferCount() cannot be used with a floating point length. Got "1.1".'
  )
})

test('numbers less than 1 will error', () => {
  expect(() => bufferCount(0)).toThrow(
    'bufferCount() cannot be used with a count less than one. Got "0".'
  )
  expect(() => bufferCount(-2)).toThrow(
    'bufferCount() cannot be used with a count less than one. Got "-2".'
  )
})