React-redux,connect函数不会使用新数据更新状态

Question

我正在使用它Redux作为视图层的Flux替代方案React.我的应用程序React和Redux方法绑定react-redux connect().运行应用程序时,它会在组件安装时调度操作,并且redux返回正确的状态.但是redux-logger,在检查this.props.session它时,组件中存储已使用新状态更新的控制台中的日志仍显示旧状态.我猜我没有connect正确使用该方法,但我也无法用它来定义问题.有没有人知道最新情况？

容器/应用

'use strict';

import React from 'react';
import {connect} from 'react-redux';
import {fetchUserSession} from 'actions/SessionActions';

class App extends React.Component {
  constructor(props) {
    super(props);
  }
  componentWillMount() {
    const {dispatch, session} = this.props;
    dispatch(fetchUserSession());
    console.log(session);
    // logs:
    // Object {currentUserId: null, errorMessage: null, isSessionValid: null}

    // store is bound to window, and the initial state is ImmutabeJS object
    console.log(window.store.getState().session.toJS());
    // logs:
    // Object {currentUserId: null, errorMessage: null, isSessionValid: false}
    // as you might noticed the isSessionValid is changed to false
  }

  render() {
    // html here 
  }
}

function mapStateToProps(state){
  return {
    session: state.session.toJS()
  };
}

export default connect(mapStateToProps)(App);

动作/ Actions.js

'use strict';

import fetch from 'isomorphic-fetch';

export const SESSION_REQUEST = 'SESSION_REQUEST';
export const SESSION_SUCCESS = 'SESSION_SUCCESS';

export function requestSession() {
  return {
    type: SESSION_REQUEST
  };
}

export function receiveSession(user) {
  return {
    type: SESSION_REQUEST,
    user
  };
}

export function fetchUserSession() {
  return dispatch => {
    dispatch(requestSession());
    return fetch(`http://localhost:5000/session`)
      .then((response) => {
        if (response.status === 404) {
          dispatch(raiseSessionFailure(response));
        }
        return response.json();
      })
      .then(userData => dispatch(receiveSession(userData)));
  };
}

减速器/ SessionReducer.js

'use strict';
import {fromJS} from 'immutable';

// UPDATE!!!
// here is the initial state
const initialState = fromJS({
  currentUserId: null,
  errorMessage: null,
  isSessionValid: null
});

function sessionReducer(state = initialState, action) {
  switch (action.type) {
    case 'SESSION_REQUEST':
      return state.update('isSessionValid', () => false);
    case 'SESSION_SUCCESS':
      console.log('Reducer: SESSION_SUCCESS');
      return state;
    case 'SESSION_FAILURE':
      console.log('Reducer: SESSION_FAILURE');
      return state;
    default:
      return state;
  }
}

export default sessionReducer;

减速器/ RootReducer

'use strict';

import {combineReducers} from 'redux';
import sessionReducer from 'reducers/SessionReducer';

const rootReducer = combineReducers({
  session: sessionReducer
});

export default rootReducer;

Answer 1

问题在于从存储中session记录变量的方式props.当您将操作分派给更新状态时,它会同步更新存储,这就是您在直接登录时看到存储已更新的原因.但是,react-redux将无法更新props,直到调用componentWillMount完成并且React有机会赶上并重新呈现具有新状态的组件.如果您稍后调度操作componentWillMount并记录session道具,您将看到它已更改以反映该操作.