Error: Reducer "auth" returned undefined when handling "@@INIT" action. To ignore an action, you must explicitly return the previous state

Question

无法弄清楚我在这方面出了什么问题。只是尝试为我的项目实践设置基本的 ducks 和 saga。

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)
  ];
}

谁能解决这个错误？

Answer 1

您需要return默认情况下的状态：

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

Error: Reducer "auth" returned undefined when handling "@@INIT" action. To ignore an action, you must explicitly return the previous state

Error: Reducer "auth" returned undefined when handling "@@INIT" action. To ignore an action, you must explicitly return the previous state

reactjs

redux

redux-thunk

redux-saga

react-redux