partition.spec.js

import {partition} from './partition'

test('with array', () => {
  const predicate = x => x > 2
  const list = [1, 2, 3, 4]

  const result = partition(predicate, list)
  const expectedResult = [
    [3, 4],
    [1, 2],
  ]

  expect(result).toEqual(expectedResult)
})

test('with object', () => {
  const predicate = (value, prop) => {
    expect(typeof prop).toBe('string')

    return value > 2
  }
  const hash = {
    a: 1,
    b: 2,
    c: 3,
    d: 4,
  }

  const result = partition(predicate)(hash)
  const expectedResult = [
    {
      c: 3,
      d: 4,
    },
    {
      a: 1,
      b: 2,
    },
  ]

  expect(result).toEqual(expectedResult)
})

test('readme example', () => {
  const list = [1, 2, 3]
  const obj = {
    a: 1,
    b: 2,
    c: 3,
  }
  const predicate = x => x > 2

  const result = [partition(predicate, list), partition(predicate, obj)]
  const expected = [
    [[3], [1, 2]],
    [
      {c: 3},
      {
        a: 1,
        b: 2,
      },
    ],
  ]
  expect(result).toEqual(expected)
})