npm install @reduxjs/toolkit react-redux

// src/app/store.js
import { configureStore } from '@reduxjs/toolkit';
import counterReducer from '../features/counter/counterSlice';
import userReducer from '../features/user/userSlice';
export const store = configureStore({
  reducer: {
    counter: counterReducer,
    user: userReducer,
  },
});
export default store;

// src/features/counter/counterSlice.js
import { createSlice } from '@reduxjs/toolkit';
const counterSlice = createSlice({
  name: 'counter',
  initialState: {
    value: 0,
    history: [],
  },
  reducers: {
    increment: (state) => {
      // Immer 允許直接修改 state
      state.value += 1;
      state.history.push(`+1 → ${state.value}`);
    },
    decrement: (state) => {
      state.value -= 1;
      state.history.push(`-1 → ${state.value}`);
    },
    incrementByAmount: (state, action) => {
      state.value += action.payload;
      state.history.push(`+${action.payload} → ${state.value}`);
    },
    reset: (state) => {
      state.value = 0;
      state.history = [];
    },
  },
});
export const { increment, decrement, incrementByAmount, reset } = counterSlice.actions;
export default counterSlice.reducer;

// src/features/user/userSlice.js
import { createSlice, createAsyncThunk } from '@reduxjs/toolkit';
import axios from 'axios';
// 創(chuàng)建異步 thunk
export const fetchUser = createAsyncThunk(
  'user/fetchUser',
  async (userId, { rejectWithValue }) => {
    try {
      const response = await axios.get(`/api/users/${userId}`);
      return response.data;
    } catch (error) {
      return rejectWithValue(error.response.data);
    }
  }
);
const userSlice = createSlice({
  name: 'user',
  initialState: {
    data: null,
    loading: false,
    error: null,
  },
  reducers: {
    clearUser: (state) => {
      state.data = null;
      state.error = null;
    },
  },
  extraReducers: (builder) => {
    builder
      .addCase(fetchUser.pending, (state) => {
        state.loading = true;
        state.error = null;
      })
      .addCase(fetchUser.fulfilled, (state, action) => {
        state.loading = false;
        state.data = action.payload;
      })
      .addCase(fetchUser.rejected, (state, action) => {
        state.loading = false;
        state.error = action.payload;
      });
  },
});
export const { clearUser } = userSlice.actions;
export default userSlice.reducer;

// src/components/Counter.jsx
import React from 'react';
import { useSelector, useDispatch } from 'react-redux';
import { increment, decrement, incrementByAmount, reset } from '../features/counter/counterSlice';
function Counter() {
  const count = useSelector((state) => state.counter.value);
  const history = useSelector((state) => state.counter.history);
  const dispatch = useDispatch();
  return (
    <div className="counter">
      <h2>計(jì)數(shù)器：{count}</h2>
      <div className="buttons">
        <button onClick={() => dispatch(decrement())}>-</button>
        <button onClick={() => dispatch(increment())}>+</button>
        <button onClick={() => dispatch(incrementByAmount(5))}>+5</button>
        <button onClick={() => dispatch(reset())}>重置</button>
      </div>
      {history.length > 0 && (
        <div className="history">
          <h3>操作歷史：</h3>
          <ul>
            {history.map((item, index) => (
              <li key={index}>{item}</li>
            ))}
          </ul>
        </div>
      )}
    </div>
  );
}
export default Counter;

// src/components/UserProfile.jsx
import React, { useEffect } from 'react';
import { useSelector, useDispatch } from 'react-redux';
import { fetchUser, clearUser } from '../features/user/userSlice';
function UserProfile({ userId }) {
  const dispatch = useDispatch();
  const { data, loading, error } = useSelector((state) => state.user);
  useEffect(() => {
    dispatch(fetchUser(userId));
  }, [userId, dispatch]);
  if (loading) return <div>加載中...</div>;
  if (error) return <div>錯(cuò)誤：{error}</div>;
  if (!data) return null;
  return (
    <div className="user-profile">
      <h2>{data.name}</h2>
      <p>郵箱：{data.email}</p>
      <button onClick={() => dispatch(clearUser())}>清除</button>
    </div>
  );
}
export default UserProfile;

src/
├── app/
│   └── store.js          # Store 配置
├── features/
│   ├── counter/
│   │   ├── counterSlice.js
│   │   └── Counter.jsx
│   └── user/
│       ├── userSlice.js
│       └── UserProfile.jsx
├── components/            # 通用組件
└── index.js              # 入口文件

// src/index.js
import React from 'react';
import ReactDOM from 'react-dom/client';
import { Provider } from 'react-redux';
import { store } from './app/store';
import App from './App';
ReactDOM.createRoot(document.getElementById('root')).render(
  <Provider store={store}>
    <App />
  </Provider>
);

// src/app/hooks.ts
import { TypedUseSelectorHook, useDispatch, useSelector } from 'react-redux';
import type { RootState, AppDispatch } from './store';
// 在整個(gè)應(yīng)用中使用這些 hooks，而非默認(rèn)的 useDispatch/useSelector
export const useAppDispatch = () => useDispatch<AppDispatch>();
export const useAppSelector: TypedUseSelectorHook<RootState> = useSelector;