drpicox/spy-middleware

Middleware that spyies all actions and allows you to wait for specific actions or events.

spyMiddleware

Middleware that spyies all actions and allows you to wait for specific actions or events.

Quick Use

Install with npm:

npm install spy-middleware

or for just testing:

npm install -D spy-middleware

Use in your code:

import { createStore, applyMiddleware } from 'redux'
import makeSpyMiddleware from 'spy-middleware'

import { fetchTopic, PUT_TOPIC } from '../actions'
import middleware from '../middleware'
import reducer from '../reducer'
import { getTopic } from '../selectors'

let spyMiddleware
let store
beforeEach(() => {
  spyMiddleware = makeSpyMiddleware()
  store = createStore(reducer, applyMiddleware(middleware, spyMiddleware))
})

test("when a fetchTopic is requested it retrieves the topic from the REST service", async () => {
  fetch.mockResponse('This is the readme')
  store.dispatch(fetchTopic('README'))

  await spyMiddleware.untilNext(PUT_TOPIC)

  const topic = getTopic(store.getState(), { name: 'README' })
  expect(topic).toEqual('This is the readme')
})

makeSpyMiddleware()

It creates a middleware compatible with redux applyMiddleware that contains specific methods to spy what is happening inside the store.

import makeSpyMiddleware from 'spy-middleware'

let spyMiddleware
beforeEach(() => {
  spyMiddleware = makeSpyMiddleware()
})

spyMiddleware

Redux middleware that has to be applied with applyMiddleware

let store
beforeEach(() => {
  store = createStore(reducer, applyMiddleware(spyMiddleware))
})

### spyMiddleware.getActions(): Action[]

Get all dispatched and reduced actions.

store.dispatch(startAction)
store.dispatch(stopAction)
store.dispatch(resumeAction)

const actions = spyMiddleware.getActions()
expect(actions).toEqual([startAction, stopAction, resumeAction])

### spyMiddleware.getAction(string|regExp|(action)=>bool): Action

Get the last action that satisfies the condition or undefined if none.

store.dispatch(startAction)
store.dispatch(stopAction)
store.dispatch(resumeAction)

const foundAction = spyMiddleware.getAction(/^S/i)
expect(foundAction).toBe(stopAction)

### spyMiddleware.untilNext(string|regExp|(action)=>bool): Promise

Returns a promise which is resolved when the matching action is dispatched and reduced.

let actionsBeforeAwait
let actionsAfterAwait

delay(1).then(() => store.dispatch(startAction))
actionsBeforeAwait = spyMiddleware.getActions()
await spyMiddleware.untilNext(START)
actionsAfterAwait = spyMiddleware.getActions()

expect(actionsBeforeAwait).toEqual([])
expect(actionsAfterAwait).toEqual([startAction])

The promise is resolved with the first action fired after untilNext call that satisfies the condition.

delay(1).then(() => store.dispatch(startAction))
const foundStartAction = await spyMiddleware.untilNext(START)

expect(foundStartAction).toBe(startAction)

### spyMiddleware.until(string|regExp|(action)=>bool): Promise

Returns a promise which is resolved when the matching action is dispatched and reduced or if a matching action was resolved in the past.

let actionFoundByUntil
let actionFoundByUntilNext

store.dispatch(startAction)
const untilFinished = spyMiddleware.until(action => {
  if (/^S/.test(action.type)) {
    actionFoundByUntil = action
    return true
  }
  return false
})
const untilNextFinished = spyMiddleware.untilNext(action => {
  if (/^S/.test(action.type)) {
    actionFoundByUntilNext = action
    return true
  }
  return false
})
store.dispatch(stopAction)

await untilFinished
await untilNextFinished

expect(actionFoundByUntil).toBe(startAction)
expect(actionFoundByUntilNext).toBe(stopAction)

The promise is resolved with the first action ever dispatched that satisfies the condition.

store.dispatch(startAction)
const foundStartAction = await spyMiddleware.untilNext(START)

expect(foundStartAction).toBe(startAction)

### ### spyMiddleware.clearActions(): void

Clears the list of dispatched actions.

store.dispatch(startAction)
store.dispatch(stopAction)

spyMiddleware.clearActions()

store.dispatch(resumeAction)

const actions = spyMiddleware.getActions()

expect(actions).toEqual([resumeAction])