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

A functional programming library.

import __ from '../../src/Function/__'
/**
 * Number -> a -> [a] -> [a]
 */
import update from '../../src/List/update'

test('update(not using __), positive number', () => {
  expect(
    update(1)(2)([1, 3, 4, 5])
  ).toEqual([1, 2, 4, 5])
})

test('update(not using __), negative number', () => {
  expect(
    update(-2)(2)([1, 3, 4, 5])
  ).toEqual([1, 3, 2, 5])
})

test('update(using __), positive number', () => {
  expect(
    update(1, __, [1, 3, 4, 5])(2)
  ).toEqual([1, 2, 4, 5])
})