为什么单击按钮时我的状态没有在 redux 中更新

Question

我正在尝试更新我的 redux 状态，但单击按钮时它似乎没有更新。我有一个“团队”下拉菜单，当单击“添加团队”按钮时，它应该更新静态数据为“团队 1”和“团队 2”，但它不会更新。对于我对 redux 的新代码量表示歉意，并且不知道问题可能出在哪里。代码如下：

Store.ts

import { createStore, applyMiddleware } from 'redux';
import { composeWithDevTools } from 'redux-devtools-extension';
import thunk from 'redux-thunk';

/* FILE DEPENDENCIES */
import RootReducer from './rootReducer';

//Fix dev tools
const Store = createStore(RootReducer, composeWithDevTools(applyMiddleware(thunk)));

export type RootStore = ReturnType<typeof RootReducer>;

export default Store;

teamsReducer.ts

import { Team } from '../Models/TeamsModels';
import { TeamsDispatchTypes, TEAMS_FAIL, TEAMS_LOADING, TEAMS_SUCCESS } from './Actions/TeamsActionTypes';

export interface IDefaultState {
    loading: boolean;
    teams?: Team[];
}

const defaultState: IDefaultState = {
    loading: false,
};

const teamsReducer = (state: IDefaultState = defaultState, action: TeamsDispatchTypes): IDefaultState => {
    switch (action.type) {
        case TEAMS_FAIL:
            return {
                loading: false,
                teams: state.teams,
            };
        case TEAMS_LOADING:
            return {
                loading: true,
                teams: state.teams,
            };
        case TEAMS_SUCCESS:
            return {
                loading: false,
                teams: action.payload,
            };
        default:
            return state;
    }
};

export default teamsReducer;

TeamsActions.ts

import { Dispatch } from 'redux';
import { Team } from '../../Models/TeamsModels';
/*FILE DEPENDENCIES*/
import { TeamsDispatchTypes, TEAMS_FAIL, TEAMS_SUCCESS } from './TeamsActionTypes';

export const GetTeams = () => (dispatch: Dispatch<TeamsDispatchTypes>) => {
    try {
        const newPayload: Team[] = [{ name: 'Team 1' }, { name: 'Team 2' }];

        dispatch({
            type: TEAMS_SUCCESS,
            payload: newPayload,
        });
    } catch (e) {
        dispatch({
            type: TEAMS_FAIL,
        });
    }
};

TeamActionTypes.ts

import { Team } from '../../Models/TeamsModels';

export const TEAMS_LOADING = 'TEAMS_LOADING';
export const TEAMS_SUCCESS = 'TEAMS_SUCCESS';
export const TEAMS_FAIL = 'TEAMS_FAIL';

export interface TeamsLoading {
    type: typeof TEAMS_LOADING;
}

export interface TeamsSuccess {
    type: typeof TEAMS_SUCCESS;
    payload: Team[];
}

export interface TeamsFail {
    type: typeof TEAMS_FAIL;
}

export type TeamsDispatchTypes = TeamsLoading | TeamsFail | TeamsSuccess;

rootReducer.ts

import { combineReducers } from 'redux';

/*FILE DEPENDENCIES*/
import TeamsReducer from './Teams/teamsReducer';

const RootReducer = combineReducers({
    teams: TeamsReducer,
});

export default RootReducer;

index.tsx

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './Component/App/App';
import reportWebVitals from './reportWebVitals';
import { Provider } from 'react-redux';
import Store from './State/Store';

ReactDOM.render(
    <Provider store={Store}>
        <App />
    </Provider>,
    document.getElementById('root'),
);

reportWebVitals();

App.tsx

import React from 'react';
import Navbar from '../Navbar/Navbar';
import { BrowserRouter as Router, Switch } from 'react-router-dom';
import './App.css';

function App(): JSX.Element {
    return (
        <div className="App">
            <Router>
                <Navbar></Navbar>
                <Switch></Switch>
            </Router>
        </div>
    );
}

export default App;

Navbar.tsx

import React from 'react';
import { NavLink } from 'react-router-dom';
import '../Navbar/Navbar.css';

import { RootStore } from '../../State/Store';
import { GetTeams } from '../../State/Teams/Actions/TeamsActions';
import { useDispatch, useSelector } from 'react-redux';

export default function Navbar(): JSX.Element {
    const dispatch = useDispatch();
    const teamsState = useSelector((state: RootStore) => state.teams);

    //Is not updating store, need to look at this
    const handleOnClick = () => {
        dispatch(GetTeams());
    };

    console.log('Teams State: ', teamsState);
    return (
        <nav className="navbar navbar-expand-lg navbar-light bg-light">
            <NavLink className="navbar-brand" to="/">
                Navbar
            </NavLink>
            <button
                className="navbar-toggler"
                type="button"
                data-toggle="collapse"
                data-target="#navbarNavDropdown"
                aria-controls="navbarNavDropdown"
                aria-expanded="false"
                aria-label="Toggle navigation"
            >
                <span className="navbar-toggler-icon"></span>
            </button>
            <div className="collapse navbar-collapse" id="navbarNavDropdown">
                <ul className="navbar-nav">
                    <li className="nav-item dropdown">
                        <a
                            className="nav-link dropdown-toggle"
                            href="#"
                            id="navbarDropdownMenuLink"
                            data-toggle="dropdown"
                            aria-haspopup="true"
                            aria-expanded="false"
                        >
                            Dropdown link
                        </a>
                        <div className="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                            <a className="dropdown-item" href="/add-team" onClick={handleOnClick}>
                                Add Team
                            </a>
                            {teamsState.teams &&
                                teamsState.teams.map((team) => (
                                    <a className="dropdown-item" href={'/' + team.name} key={team.name}>
                                        {team.name}
                                    </a>
                                ))}
                        </div>
                    </li>
                </ul>
            </div>
        </nav>
    );
}

Answer 1

发生的情况是操作被分派并且团队保存在状态中，但随后整个页面立即刷新并且数据丢失。这是因为您的“添加团队”是一个带有href 标签的a 元素，因此单击该链接会调用handleOnClick，但它也会导致导航。由于您仅使用 a 而不是 react-router-dom 中的 Link，因此该导航事件未正确处理。

当我从“添加团队”链接中删除 href 后，团队就开始出现了，但如果不是链接，则使用 a 不是一个好习惯，因此您应该使用 div 或取而代之的是其他一些 HTML 元素。由于单击a 标签，单击单个团队名称仍然存在相同的数据丢失问题，因此您需要在此处使用Link。