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

Reactive programming tools using the WHATWG Streams API.

import { fromTimeline } from '@johngw/stream-jest'
import {
  debounce,
  DebounceBackOffBehavior,
  DebounceLeadingBehavior,
  DebounceTrailingBehavior,
} from '@johngw/stream/transformers/debounce'

test('trailing only (by default)', async () => {
  await expect(
    fromTimeline(`
    --1--2------T10--|
    `).pipeThrough(debounce(10))
  ).toMatchTimeline(`
    -----T10-2--------
  `)
})

test('leading only', async () => {
  await expect(
    fromTimeline(`
    --1--2--T10-|
    `).pipeThrough(debounce(10, new DebounceLeadingBehavior()))
  ).toMatchTimeline(`
    --1--
  `)
})

test('leading and trailing', async () => {
  await expect(
    fromTimeline(`
    -1-2-3--------------|
    `).pipeThrough(
      debounce(10, [
        new DebounceLeadingBehavior(),
        new DebounceTrailingBehavior(),
      ])
    )
  ).toMatchTimeline(`
    -1-T10-3-
  `)
})

test('back off', async () => {
  await expect(
    fromTimeline(`
    -1-2-3-4-T45-5----|
  `).pipeThrough(
      debounce(10, [
        new DebounceLeadingBehavior(),
        new DebounceBackOffBehavior({ inc: (x) => x * 2, max: 45 }),
      ])
    )
  ).toMatchTimeline(`
    -1-----T45---5----
  `)
})