moy-fp/test/List/lastList.test.js

A functional programming library.

import __ from '../../src/Function/__'
/**
 * [a] -> a | undefined
 */
import lastList from '../../src/List/lastList'

test('lastList(not using __), not empty array', () => {
  expect(
    lastList([1, 2, 3, 4])
  ).toBe(4)
})

test('lastList(not using __), empty array', () => {
  expect(
    lastList([])
  ).toBeUndefined()
})

test('lastList(using __), not empty array', () => {
  expect(
    lastList(__)([1, 2, 3, 4])
  ).toBe(4)
})