Discord.js |显示ID中的用户名返回undefined

const Discord = require('discord.js');
const client = new Discord.Client();

client.on('ready', () => {
  console.log(`Logged in as ${client.user.tag}`);
});

client.on('message', async (message) => {
  if (message.content.startsWith('!getUsername')) {
    const userId = message.content.split(' ')[1]; // 获取用户ID
    try {
      const user = await client.users.fetch(userId); // 获取User对象
      const username = user.username; // 获取用户名
      message.channel.send(`User ID ${userId} 的用户名是：${username}`);
    } catch (error) {
      console.error(error);
      message.channel.send('无法获取用户名，请检查用户ID是否正确。');
    }
  }
});

client.login('YOUR_DISCORD_BOT_TOKEN');