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

A functional programming library.

import Identity from '../../../src/Functor/Identity/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 => `Identity(${x.value})`

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

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

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

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

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

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

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