为什么没有redux-thunk的redux-observable无法正常工作？

Question

我完全遵循文档，并且总是得到

  

动作必须是普通对象

如果我将applyMiddleware放到epicMiddleware中，则一切正常

// src/store/index.js

import { createStore, combineReducers, applyMiddleware } from 'redux'
import { createEpicMiddleware, combineEpics } from 'redux-observable'
import thunk from 'redux-thunk'
import users from './users/reducer'
import countEpic from './users/epics'

const epicMiddleware = createEpicMiddleware()

const store = createStore(
  combineReducers({
    users,
  }),
  applyMiddleware(thunk, epicMiddleware)
)

epicMiddleware.run(combineEpics(countEpic))

export default store

// src/store/users/epics.js

import { mapTo } from 'rxjs/operators'
import { ofType } from 'redux-observable'

const countEpic = action$ =>
  action$.pipe(
    ofType('CLICK'),
    mapTo({ type: 'INCREMENT' })
  )

export default countEpic