Question

我对编码还比较陌生，目前正在尝试制作一个简单的音乐机器人。要求很高的功能之一是“现在播放”嵌入，每5秒更新一次。几天前，我曾尝试在Stack Overflow上的其他人的帮助下实施此操作，但由于我只做了discord.js几个月了，所以我收到了一个我不知道如何解决的错误。我将向您展示有效的代码和无效的代码，谢谢您的事先帮助！

const queue = message.client.queue.get(message.guild.id);
if (!queue)
 return message.channel.send({
  embed: { color: 'ff0000', description: `Nothing's playing right now.` },
 });
const song = queue.songs[0];
const seek =
 (queue.connection.dispatcher.streamTime -
  queue.connection.dispatcher.pausedTime) /
 1000;
const left = song.duration - seek;

let nowPlaying = new MessageEmbed()
 .setTitle('Now playing:')
 .setDescription(`${song.title}`)
 .setColor('#ff0000')
 .setThumbnail('https://img.icons8.com/clouds/2x/play.png')
 .addField(
  '\u200b',
  new Date(seek * 1000).toISOString().substr(11, 8) +
   '[ ' +
   createBar(song.duration == 0 ? seek : song.duration, seek, 10)[0] +
   '] ' +
   (song.duration == 0
    ? ' ◉ LIVE'
    : new Date(song.duration * 1000).toISOString().substr(11, 8)),
  false
 );

if (song.duration > 0)
 nowPlaying.setFooter(
  'Time Remaining: ' + new Date(left * 1000).toISOString().substr(11, 8)
 );

message.channel.send(nowPlaying);

然后是具有上述错误的代码：

const queue = message.client.queue.get(message.guild.id);
if (!queue)
 return message.channel.send({
  embed: { color: 'ff0000', description: `Nothing's playing right now.` },
 });
const song = queue.songs[0];
const seek =
 (queue.connection.dispatcher.streamTime -
  queue.connection.dispatcher.pausedTime) /
 1000;
const left = song.duration - seek;

let nowPlaying = new MessageEmbed()
 .setDescription(`Now Playing:\n**${song.title}**`)
 .setColor('#ff0000')
 .addField(
  '\u200b',
  new Date(seek * 1000).toISOString().substr(11, 8) +
   ' **[** ' +
   createBar(song.duration == 0 ? seek : song.duration, seek, 10)[0] +
   ' **]** ' +
   (song.duration == 0
    ? ' ◉ LIVE'
    : new Date(song.duration * 1000).toISOString().substr(11, 8)),
  false
 );

message.channel.send(nowPlaying).then((message) => {
 var countdown = song.duration;

 const interval = setInterval(() => {
  const queue = message.client.queue.get(message.guild.id);
  const song = queue.songs[0];
  const seek =
   (queue.connection.dispatcher.streamTime -
    queue.connection.dispatcher.pausedTime) /
   1000;
  const left = song.duration - seek;

  let nowPlayingTest = new MessageEmbed()
   .setDescription(`Now Playing:\n**${song.title}**`)
   .setColor('#ff0000')
   .addField(
    '\u200b',
    new Date(seek * 1000).toISOString().substr(11, 8) +
     ' **[** ' +
     createBar(song.duration == 0 ? seek : song.duration, seek, 10)[0] +
     ' **]** ' +
     (song.duration == 0
      ? ' ◉ LIVE'
      : new Date(song.duration * 1000).toISOString().substr(11, 8)),
    false
   );

  if (countdown < 0) clearInterval(interval);

  message.edit(nowPlayingTest);
 }, 5000);
});

感谢您的帮助！

Answer 1

错误消息Cannot read property 'songs' of undefined表示.songs之前的变量未定义。在这种情况下，queue是未定义的。

在有效的代码中，您可以正确地进行处理：在访问queue之前检查.songs是否未定义。

if (!queue) // handle if queue is undefined
  return message.channel.send({
    embed: { color: 'ff0000', description: `Nothing's playing right now.` },
  });
// queue is guaranteed to be not undefined here
const song = queue.songs[0];

但是，在导致错误的代码中，您没有在setInterval处理程序中对其进行处理。

/** in setInterval() **/
const queue = message.client.queue.get(message.guild.id);
// queue may be undefined!
const song = queue.songs[0]; // error occurs if queue is undefined!

要纠正该错误，您需要做的就是像处理代码一样处理未定义的情况。例如：

const queue = message.client.queue.get(message.guild.id);
if (!queue) return clearInterval(interval); // when queue is gone, stop editing the embed message
// queue is guaranteed to be not undefined here!
const song = queue.songs[0]; // OK!

错误：无法读取未定义的属性“歌曲”-discord.js

1 个答案: