o/src/__tests__/each.spec.ts

common object helper functions

import each from '../each'
import { OObject, EachCallback } from '../types'

describe('each', (): void => {
  const obj = {
    a: 1,
    b: 2,
    c: {
      d: 3,
      e: {
        f: 4
      }
    }
  }

  test('should foreach over object keys', (): void => {
    const mockCallback = jest.fn()

    each(obj, mockCallback)

    expect(mockCallback.mock.calls).toHaveLength(3)
  })

  test('should foreach over object deeply when follow is true', (): void => {
    const mockCallback = jest.fn()

    each(obj, mockCallback, {
      follow: true
    })

    expect(mockCallback.mock.calls).toHaveLength(4)
  })

  test('should not run callback if object is empty', (): void => {
    const mockCallback = jest.fn()

    each({}, mockCallback)

    expect(mockCallback.mock.calls).toHaveLength(0)
  })

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

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