title: oldState and newState undefined
body: <p>I need help. I am new at discord.js and still learning
  this my event handling I code based guide documentation:</p>
  <pre><code>const fs = require('fs');
  const { Client, Intents } = require('discord.js');
  const { token } = require('./config.json');
  
  const client = new Client({ intents: [Intents.FLAGS.GUILDS, Intents.FLAGS.GUILD_VOICE_STATES] });
  
  const eventFiles = fs.readdirSync('./events').filter(file =&gt; file.endsWith('.js'));
  
  for (const file of eventFiles) {
      const event = require(`./events/${file}`);
      if (event.once) {
          client.once(event.name, (...args) =&gt; event.execute(...args));
      } else {
          client.on(event.name, (...args) =&gt; event.execute(...args));
      }
  }
  
  client.login(token);
  </code></pre>
  <p>and here I try to create the event <code>voiceStateUpdate</code>:</p>
  <pre><code>module.exports = {
      name: 'voiceStateUpdate', 
      execute(newState, oldState) {
          console.log(`VOICEState Ready`);
              if(newState.channelID === null) //left
                  console.log('user left channel', oldState.channelID);
              else if(oldState.channelID === null) // joined
                  console.log('user joined channel', newState.channelID);
              else // moved
                  console.log('user moved channels', oldState.channelID, newState.channelID);
          
          },
  };
  </code></pre>
  <p>I ran the bot, and I found that <code>oldState</code> and <code>newState</code> are undefined. So where must I put those two if I use event handling like that? Or am I doing something wrong? Thank you.</p>