无法读取未定义的属性 'set' | JavaScript | Discord.js v12

Question

我目前正在为我的机器人做一些命令处理，但我遇到了这个错误，我似乎不明白为什么会发生

这里是错误：

(node:10136) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'set' of undefined
at Object.execute (D:\Chest\Projects\Discord\terminalv2\commands\music\execute.js:36:28)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:93:5)

有问题的行是 36，但它是定义的。我不知道该怎么办。

这是我的代码：

const external = require('./../../externalCommands');
const ytdl = require("ytdl-core");

module.exports = {
name: 'play',
aliases: ['p'],

async execute(message) {
    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! *bap*");
    }

    if (!args[1]) {
        return message.channel.send("You need to specify a youtube link! *bap*");
    }

    const songInfo = await ytdl.getInfo(args[1]);
    const song = {
        title: songInfo.videoDetails.title,
        url: songInfo.videoDetails.video_url,
    };

    if (!external.serverQueue) {
        const queueContruct = {
            textChannel: message.channel,
            voiceChannel: voiceChannel,
            connection: null,
            songs: [],
            volume: 25,
            playing: true,
        };

        external.queue.set(message.guild.id, queueContruct);
        queueContruct.songs.push(song);
        
        var connection = await voiceChannel.join();
        queueContruct.connection = connection;
        external.play(message.guild, queueContruct.songs[0]);
    } else {
        external.serverQueue.songs.push(song);
        return message.channel.send(`I added **${song.title}** to the queue UwU`);
    }
},
};