throttle-does-not-guarantee-latest-call

throttle-vs-debounce.js

import {throttle, debounce} from 'lodash'
const delay = () => new Promise(r => setTimeout(r, 100))

describe('throttle vs debouce', () => {
  beforeEach(() => {
    console.log = jest.fn()
  })
  it('throttle does not guarantee about execute latest call', async (done) => {
    const i = throttle(x => console.log(x), 300)
    let count = 0

    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    await delay()
    expect(count).toEqual(10)
    expect(console.log).not.toHaveBeenLastCalledWith(10)
    done()
  })
  it('debounce guarantee about execute latest call', async (done) => {
    const i = debounce(x => console.log(x), 200)
    let count = 0

    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    i(++count)
    await delay()
    await delay()
    await delay()
    expect(count).toEqual(9)
    // expect(console.log).toHaveBeenCalledTimes(1)
    expect(console.log).toHaveBeenLastCalledWith(9)
    done()
  })
})