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

A functional programming library.

import __ from '../../src/Function/__'
/**
 * b -> a -> [a, b]
 */
import pair from '../../src/List/pair'

test('pair(not using __)', () => {
  expect(
    pair(2)(1)
  ).toEqual([1, 2])
})

test('pair(using __)', () => {
  expect(
    pair(__, 1)(2)
  ).toEqual([1, 2])
})