在使用renderUI时，使侧边栏选项卡默认处于选中状态

import React, { useState } from 'react';

const Sidebar = () => {
  const [activeTab, setActiveTab] = useState(0); // 默认选中第一个选项卡

  const handleTabClick = (index) => {
    setActiveTab(index);
  };

  return (
    <div>
      <ul>
        <li className={activeTab === 0 ? 'active' : ''} onClick={() => handleTabClick(0)}>选项卡1</li>
        <li className={activeTab === 1 ? 'active' : ''} onClick={() => handleTabClick(1)}>选项卡2</li>
        <li className={activeTab === 2 ? 'active' : ''} onClick={() => handleTabClick(2)}>选项卡3</li>
      </ul>
    </div>
  );
};

export default Sidebar;