2023/06/25　追記

discord.js v14で書き直し、いくつかの機能を追加した新バージョンをgithubで公開しました。
また、長い間オフラインだったSakuraMusicを使用可能な状態に変更しました。
招待リンクはこちら

以下古い内容

Youtubeが7日間以内のサービス停止を求めたためRythmは音楽再生のサービスを停止してしまいました

別のものに乗り換えようかと思ったのですが今後有名なものは使えなくなりそうなので自作してみました。
招待リンクはこれになります。よかったら使ってみてください。

コードはここのものを改造して作っています。

以下はソースコードの一部です。
tokenやprefixはご自分のものに置き換えてください。
また、toHms関数はここのものを改造して使用しています。
この記事のコードで実装されている機能は以下の写真のとおりです。

環境は
Node.js 14
Discord.js v12.5.3
となります
discord.js v12はサポートが切れているため今後v13にコードを書き換えます。

main.js

const Discord = require("discord.js");
const prefix = "";
const token = "";
const ytdl = require("ytdl-core");
const client = new Discord.Client();
const queue = new Map();
client.on("ready", () => {
  console.log("Ready!");
});
client.on("reconnecting", () => {
  console.log("Reconnecting!");
});
client.on("disconnect", () => {
  console.log("Disconnect!");
});
client.on("message", async message => {
  if (message.author.bot) return;
  if (!message.content.startsWith(prefix)) return;
  const serverQueue = queue.get(message.guild.id);
  if (message.content.startsWith(`${prefix}play`)) {
    execute(message, serverQueue);
    return;
  } else if (message.content.startsWith(`${prefix}skip`)) {
    skip(message, serverQueue);
    return;
  } else if (message.content.startsWith(`${prefix}stop`)) {
    stop(message, serverQueue);
    return;
  } else if (message.content.startsWith(`${prefix}loop`)) {
    loop(message, serverQueue);
    return;
  } else if (message.content.startsWith(`${prefix}queueloop`)) {
    queueloop(message, serverQueue);
    return;
  } else if (message.content.startsWith(`${prefix}help`)) {
    help(message);
    return;
  } else if (message.content.startsWith(`${prefix}nowplaying`)) {
    nowplaying(message, serverQueue);
    return;
  } else {
    message.channel.send("You need to enter a valid command!");
  }
});
async function execute(message, serverQueue) {
  var err = false;
  const args = message.content.split(" ");
  const voiceChannel = message.member.voice.channel;
  if (!voiceChannel) return message.channel.send("You need to be in a voice channel to play music!");
  const permissions = voiceChannel.permissionsFor(message.client.user);
  if (!permissions.has("CONNECT") || !permissions.has("SPEAK")) {
    return message.channel.send("I need the permissions to join and speak in your voice channel!");
  }
  const songInfo = await ytdl.getInfo(args[1]).catch(error => {
    err = true;
    message.channel.send("Oops, there seems to have been an error.\nPlease check the following points.\n*Is the URL correct?\n*Are you using a URL other than Youtube?\n*Is the URL shortened? \nIf the problem still persists, please wait a while and try again.")
  });
  if (err) return;
  const song = {
    title: songInfo.videoDetails.title,
    url: songInfo.videoDetails.video_url,
    totalsec: songInfo.videoDetails.lengthSeconds,
    viewcount: songInfo.videoDetails.viewCount,
    author: {
      name: songInfo.videoDetails.author.name,
      url: songInfo.videoDetails.author.channel_url,
      subscriber_count: songInfo.videoDetails.author.subscriber_count,
      verified: songInfo.videoDetails.author.verified
    },
    isPrivate: songInfo.videoDetails.isPrivate,
    likes: songInfo.videoDetails.likes,
    dislikes: songInfo.videoDetails.dislikes,
    thumbnail: songInfo.videoDetails.thumbnails[Object.keys(songInfo.videoDetails.thumbnails).length - 1].url
  };
  if (!serverQueue) {
    const queueContruct = {
      textChannel: message.channel,
      voiceChannel: voiceChannel,
      connection: null,
      songs: [],
      volume: 5,
      playing: true,
      loop: false,
      queueloop: false,
      starttimestamp: 0
    };
    queue.set(message.guild.id, queueContruct);
    queueContruct.songs.push(song);
    try {
      var connection = await voiceChannel.join();
      queueContruct.connection = connection;
      play(message.guild, queueContruct.songs[0]);
    } catch (err) {
      console.log(err);
      queue.delete(message.guild.id);
      return message.channel.send(err);
    }
  } else {
    serverQueue.songs.push(song);
    return message.channel.send(`${song.title} has been added to the queue!`);
  }
}

function skip(message, serverQueue) {
  if (!message.member.voice.channel) return message.channel.send("You have to be in a voice channel to stop the music!");
  if (!serverQueue) return message.channel.send("There is no song that I could skip!");
  serverQueue.connection.dispatcher.end();
}

function stop(message, serverQueue) {
  if (!message.member.voice.channel) return message.channel.send("You have to be in a voice channel to stop the music!");
  if (!serverQueue) return message.channel.send("There is no song that I could stop!");
  serverQueue.songs = [];
  serverQueue.connection.dispatcher.end();
  message.channel.send("See you! :wave:");
}
async function play(guild, song) {
  const serverQueue = queue.get(guild.id);
  if (!song) {
    serverQueue.voiceChannel.leave();
    queue.delete(guild.id);
    return;
  }
  const dispatcher = serverQueue.connection.play(ytdl(song.url)).on("finish", () => {
    finishsong = serverQueue.songs.shift();
    if (serverQueue.loop) {
      serverQueue.songs.unshift(finishsong);
    } else if (serverQueue.queueloop) {
      serverQueue.songs.push(finishsong);
    }
    play(guild, serverQueue.songs[0]);
  }).on("error", error => message.channel.send("Oops, there seems to have been an error.\nPlease check the following points.\n*Is the URL correct?\n*Are you using a URL other than Youtube?\n*Is the URL shortened? \nIf the problem still persists, please wait a while and try again."))
  dispatcher.setVolumeLogarithmic(serverQueue.volume / 5);
  serverQueue.textChannel.send(`Start playing: **${song.title}**`);
  serverQueue.starttimestamp = Date.now()
}

function loop(message, serverQueue) {
  if (!message.member.voice.channel) return message.channel.send("You have to be in a voice channel to stop the music!");
  if (!serverQueue) return message.channel.send("There is no song that I could loop!");
  if (serverQueue.loop) {
    serverQueue.loop = false;
    message.channel.send("Loop is Disabled!");
  } else {
    serverQueue.loop = true;
    message.channel.send("Loop is Enabled!");
  }
}

function queueloop(message, serverQueue) {
  if (!message.member.voice.channel) return message.channel.send("You have to be in a voice channel to stop the music!");
  if (!serverQueue) return message.channel.send("There is no song that I could loop!");
  if (serverQueue.queueloop) {
    serverQueue.queueloop = false;
    message.channel.send("Queue loop is Disabled!");
  } else {
    serverQueue.queueloop = true;
    message.channel.send("Queue loop is Enabled!");
  }
}

function help(message) {
  message.channel.send("🌸SakuraMusic🌸\n[Command List]\n\n¥play (URL) - Plays the song specified in the URL. Keyword search is not available.\n\n¥stop - Stops playing the song and exits the voice channel.\n\n¥skip - Switch to the next song in the queue if there is one.\n\n¥loop - Plays the current song in a loop. Run it again to cancel the loop setting.\n\n¥queueloop - plays through the songs in the queue, then returns to the beginning of the queue and continues playing. Run it again to cancel the loop setting.\n\n¥help - Brings up this message.\n\n¥nowplaying - Show the infomation about the music.");
}

function nowplaying(message, serverQueue) {
  if (!message.member.voice.channel) return message.channel.send("You have to be in a voice channel to stop the music!");
  if (!serverQueue) return message.channel.send("There is no song!");
  var timestamp = Date.now();
  var playsec = Math.floor(timestamp / 1000)- Math.floor(serverQueue.starttimestamp / 1000);
  
  function toHms(t) {
	var hms = "";
	var h = t / 3600 | 0;
	var m = t % 3600 / 60 | 0;
	var s = t % 60;

	if (h != 0) {
		hms = h + ":" + padZero(m) + ":" + padZero(s);
	} else if (m != 0) {
		hms = m + ":" + padZero(s);
	} else {
		hms = "0:" + padZero(s);
	}

	return hms;

	function padZero(v) {
		if (v < 10) {
			return "0" + v;
		} else {
			return v;
		}
	}
}
  
  var playtimetext = toHms(playsec);
  
  var musicplaytimetext = toHms(serverQueue.songs[0].totalsec)
  
  function getprogress(nowsec,allsec){
    var oneblockamount = allsec / 20;
    var nowblock = Math.floor(nowsec / oneblockamount);
    var playblock = "■";
    var noplayblock = "□";
    var progresstext = "[" + playblock.repeat(((nowblock - 1) < 0) ? "0" : nowblock - 1) + "☆" + noplayblock.repeat(20 - nowblock) + "]";
    return progresstext;
  }
  
  var nowprogresstext = getprogress(playsec, serverQueue.songs[0].totalsec);
  
  
  const embed = {
    "title": serverQueue.songs[0].title,
    "url": serverQueue.songs[0].url,
    "color": Math.floor(Math.random() * 16777214) + 1,
    "thumbnail": {
      "url": serverQueue.songs[0].thumbnail
    },
    "footer": {
      "text": "SakuraMusic"
    },
    "author": {
      "name": serverQueue.songs[0].author.name,
      "url": serverQueue.songs[0].author.url
    },
    "fields": [{
      "name": "channel",
      "value": serverQueue.songs[0].author.name
    }, {
      "name": "Play time",
      "value": playtimetext,
      "inline": true
    }, {
      "name": "Music length",
      "value": musicplaytimetext,
      "inline": true
    }, {
      "name": "Progress",
      "value": nowprogresstext
    }, {
      "name": "viewCount",
      "value": serverQueue.songs[0].viewcount,
      "inline": true
    }, {
      "name": "likes",
      "value": serverQueue.songs[0].likes,
      "inline": true
    }, {
      "name": "dislikes",
      "value": serverQueue.songs[0].dislikes,
      "inline": true
    }, {
      "name": "Channel:subscriber",
      "value": serverQueue.songs[0].author.subscriber_count,
      "inline": true
    }, {
      "name": "Channel:verified",
      "value": serverQueue.songs[0].author.verified,
      "inline": true
    }]
  };
  message.channel.send({
    embed
  });
}

client.on("voiceStateUpdate",  async (oldState, newState) => {
  if(oldState.channelID !=null && newState.channelID === null){
  var membercount = await client.channels.cache.find(channel => channel.id == oldState.channelID);
     if (membercount.members.size <= 1) {
            const serverQueue = queue.get(membercount.guild.id);
            serverQueue.songs = [];
            serverQueue.connection.dispatcher.end();
            serverQueue.textChannel.send("See you! :wave:\nHint: When the voice channel is empty, I will leave automatically.");
     }
   }
});
client.login(token);