moy-fp/test/Functor/IO/index.test.js

A functional programming library.

import IO from '../../../src/Functor/IO/index'

/**
 * you should not use this similar funciton to get value anywhere in your application
 * if you must need the inner value, you may need Comonad
 * here is just simple for test
 */
const inspect = x => `IO(${x.unsafePerformIO()})`

test('test IO', () => {
  expect(
    inspect(IO(() => 12))
  ).toBe('IO(12)')
})

test('test of', () => {
  expect(
    inspect(IO.of(12))
  ).toBe('IO(12)')
})

test('test map', () => {
  expect(
    inspect(IO.of(12).map(x => x + 1))
  ).toBe('IO(13)')
})

test('test join', () => {
  expect(
    inspect(IO.of(
      IO.of(12)
    ).join())
  ).toBe('IO(12)')
})

test('test chain', () => {
  expect(
    inspect(IO.of(12).chain(
      x => IO.of(x + 1)
    ))
  ).toBe('IO(13)')
})

test('test ap', () => {
  expect(
    inspect(IO.of(x => x + 1).ap(
      IO.of(12)
    ))
  ).toBe('IO(13)')
})

test('test Object.prototype.toString.call',() => {
  expect(
    Object.prototype.toString.call(
      IO.of(12)
    )
  ).toBe('[object IO]')
})