React useReducer清空initialState

import React, { useReducer } from 'react';

const initialState = {
  count: 0,
  message: 'Hello, world!',
};

const reducer = (state, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return { ...state, count: state.count + 1 };
    case 'DECREMENT':
      return { ...state, count: state.count - 1 };
    case 'RESET':
      return initialState;
    case 'UPDATE_MESSAGE':
      return { ...state, message: action.payload };
    default:
      return state;
  }
};

const Counter = () => {
  const [state, dispatch] = useReducer(reducer, initialState);

  const handleReset = () => {
    dispatch({ type: 'RESET' });
  };

  return (
    <div>
      <p>Count: {state.count}</p>
      <p>Message: {state.message}</p>
      <button onClick={() => dispatch({ type: 'INCREMENT' })}>Increment</button>
      <button onClick={() => dispatch({ type: 'DECREMENT' })}>Decrement</button>
      <button onClick={handleReset}>Reset</button>
      <button onClick={() => dispatch({ type: 'UPDATE_MESSAGE', payload: 'New message' })}>Update Message</button>
    </div>
  );
};

export default Counter;