o/src/__tests__/sort.spec.ts

common object helper functions

import sort from '../sort'
import { OObject, SortCallback } from '../types'

describe('sort', (): void => {
  test('should return a new object not a reference', (): void => {
    const obj = {
      a: 1,
      b: 2
    }

    const result = sort(obj, (): number => 1)
    result.a = 2

    expect(typeof result).toBe('object')
    expect(obj.a).toBe(1)
  })

  test('should evaluate all key/values', (): void => {
    const obj = {
      a: 1,
      b: 2,
      c: 3
    }

    const cb = jest.fn()

    sort(obj, cb)

    expect(cb.mock.calls).toHaveLength(2)
  })

  test('should sort the object via the callback evaluation', (): void => {
    const obj = {
      e: 1,
      d: 2,
      b: 3,
      a: 4,
      c: 5
    }

    const result = sort(obj, (a, b): number => {
      if (a.key < b.key) return -1
      if (a.key > b.key) return 1
      return 0
    })
    const keys = Object.keys(result)

    expect(keys[0]).toBe('a')
    expect(keys[1]).toBe('b')
    expect(keys[2]).toBe('c')
    expect(keys[3]).toBe('d')
    expect(keys[4]).toBe('e')
  })

  test('should throw TypeError for invalid arguments', (): void => {
    const invalidObj: unknown = 'testing'
    const invalidCallback: unknown = 'testing'
    const invalidFollow: unknown = 'testing'

    expect((): OObject => sort(invalidObj as OObject, jest.fn()))
      .toThrow(new TypeError('Expected Object, got string testing'))
    expect((): OObject => sort({}, invalidCallback as SortCallback))
      .toThrow(new TypeError('Expected Function, got string testing'))
    expect((): OObject => sort({}, jest.fn(), {
      follow: invalidFollow as boolean
    }))
      .toThrow(new TypeError('Expected Boolean, got string testing'))
  })
})