如何编写单个缩减程序来处理redux中的不同操作？

// 定义初始状态
const initialState = {
  count: 0,
  message: ''
};

// 定义操作类型
const INCREMENT = 'INCREMENT';
const DECREMENT = 'DECREMENT';
const UPDATE_MESSAGE = 'UPDATE_MESSAGE';

// 定义缩减程序
const reducer = (state = initialState, action) => {
  switch (action.type) {
    case INCREMENT:
      return {
        ...state,
        count: state.count + 1
      };
    case DECREMENT:
      return {
        ...state,
        count: state.count - 1
      };
    case UPDATE_MESSAGE:
      return {
        ...state,
        message: action.payload
      };
    default:
      return state;
  }
};

// 创建Redux存储
const store = Redux.createStore(reducer);

// 分发操作
store.dispatch({ type: INCREMENT });
store.dispatch({ type: DECREMENT });
store.dispatch({ type: UPDATE_MESSAGE, payload: 'Hello Redux!' });

// 获取当前状态
const currentState = store.getState();
console.log(currentState);