redux-starter-kit/src/createAction.test.ts

A simple set of tools to make using Redux easier

import { createAction, getType } from './createAction'

describe('createAction', () => {
  it('should create an action', () => {
    const actionCreator = createAction<string>('A_TYPE')
    expect(actionCreator('something')).toEqual({
      type: 'A_TYPE',
      payload: 'something'
    })
  })

  describe('when stringifying action', () => {
    it('should return the action type', () => {
      const actionCreator = createAction('A_TYPE')
      expect(`${actionCreator}`).toEqual('A_TYPE')
    })
  })

  describe('when passing a prepareAction method only returning a payload', () => {
    it('should use the payload returned from the prepareAction method', () => {
      const actionCreator = createAction('A_TYPE', (a: number) => ({
        payload: a * 2
      }))
      expect(actionCreator(5).payload).toBe(10)
    })
    it('should not have a meta attribute on the resulting Action', () => {
      const actionCreator = createAction('A_TYPE', (a: number) => ({
        payload: a * 2
      }))
      expect('meta' in actionCreator(5)).toBeFalsy()
    })
  })

  describe('when passing a prepareAction method returning a payload and meta', () => {
    it('should use the payload returned from the prepareAction method', () => {
      const actionCreator = createAction('A_TYPE', (a: number) => ({
        payload: a * 2,
        meta: a / 2
      }))
      expect(actionCreator(5).payload).toBe(10)
    })
    it('should use the meta returned from the prepareAction method', () => {
      const actionCreator = createAction('A_TYPE', (a: number) => ({
        payload: a * 2,
        meta: a / 2
      }))
      expect(actionCreator(10).meta).toBe(5)
    })
  })

  describe('when passing a prepareAction that accepts multiple arguments', () => {
    it('should pass all arguments of the resulting actionCreator to prepareAction', () => {
      const actionCreator = createAction(
        'A_TYPE',
        (a: string, b: string, c: string) => ({
          payload: a + b + c
        })
      )
      expect(actionCreator('1', '2', '3').payload).toBe('123')
    })
  })
})

describe('getType', () => {
  it('should return the action type', () => {
    const actionCreator = createAction('A_TYPE')
    expect(getType(actionCreator)).toEqual('A_TYPE')
  })
})