更新状态变量，而不更改渲染时分配给它们的其他状态的值

class ExampleComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0,
      name: 'React'
    };
  }

  incrementCount = () => {
    this.setState(prevState => ({
      count: prevState.count + 1
    }));
  };

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <p>Name: {this.state.name}</p>
        <button onClick={this.incrementCount}>Increment Count</button>
      </div>
    );
  }
}

import React, { useState } from 'react';

function ExampleComponent() {
  const [state, setState] = useState({
    count: 0,
    name: 'React'
  });

  const incrementCount = () => {
    setState(prevState => ({
      ...prevState,
      count: prevState.count + 1
    }));
  };

  return (
    <div>
      <p>Count: {state.count}</p>
      <p>Name: {state.name}</p>
      <button onClick={incrementCount}>Increment Count</button>
    </div>
  );
}