Reactjs React Redux:未捕获错误：预期减速器是一个函数

我正在尝试在app.js文件中集成减缩器，但不断出现以下错误： React-Redux:未捕获错误：预期减速器是一个函数。 代码如下所示：

reducers/booksReducers.js文件

"use strict"

export function booksReducers(state={ books: [] }, action) {
  switch (action.type) {

    case 'POST_BOOK':
      // let books = state.books.concat(action.payload);
      // return {books};
      return { books: [...state.books, ...action.payload] }
      break;

    default:
      break;
  }
  return state;
}

reducers/index.js文件

"use strict"

import { combineReducers } from 'redux';

// HERE IMPORT REDUCERS TO BE COMBINED
import { booksReducers } from './booksReducers';

//HERE COMBINE THE REDUCERS
export default combineReducers({
  books: booksReducers
})

主app.js文件：

import { createStore } from 'redux';

import  { reducers } from './reducers/index';

const store = createStore(reducers);

store.subscribe(() => {
  console.log('current state is ', store.getState());
});

store.dispatch({
  type: 'POST_BOOK',
  payload: [
  {
    id: 1,
    title: 'Book Title',
    description: 'Book Description'
  },
  {
    id: 2,
    title: 'Second Book Title',
    description: 'Second Book Description'
  },
]
});

我不确定我错在哪里。有人能告诉我这里出了什么问题吗

---

谢谢

在主app.js文件中，替换

从'./reducers/index'导入{reducers}

与

从“./reducers/index”导入减缩器

与redcuers/index.js一样，
combinereducer
作为默认值导出。所以，您不需要
{}