Reactjs 错误：在处理“@@INIT”操作时，还原程序“auth”返回未定义。若要忽略操作，必须显式返回上一个状态

我想不出我在这件事上做错了什么。只是试着为我的项目实践准备一些基本的细节和故事

Ducks/auth.js

    const action = name => `/auth/${name}`;

export const FETCH = action('FETCH');

export const fetchUser = (user) => ({ type: FETCH, user });

const auth = (state = null, action) => {
  switch (action.type) {
    default:
      return console.log('Hello World');
  }
};

export default auth;

Sagas/auth.js

import {
  fork,
  takeLatest,
} from 'redux-saga/effects';
import * as actions from 'ducks/auth';

export function* fetchUser() {
  yield console.log('Hello World');
}

export function* watchFetchUser() {
  yield takeLatest(actions.FETCH, fetchUser);
}

export default function* rootSaga() {
  yield [
    fork(watchFetchUser)
  ];
}

---

有人能解决此错误吗？

在默认情况下，您需要返回状态：

const auth = (state = null, action) => {
  switch (action.type) {
    default:
      console.log('Hello World')
      return state;
  }
};