TravBot-v3/docs/MusicStructure.md

The commands

- "mhelp"   - Display a help embed.
- "play"    - Adds a song to the queue and plays it.
- "skip"    - Skips the currently playing track.
- "queue"   - Shows the current queue.
- "stop"    - Stops currently playing media and leaves the voice channel.
- "np"      - Displays the currently playing track.
- "pause"   - Pauses the currently playing track.
- "resume"  - Resumes the currently paused track.
- "volume"  - Changes the global volume of the bot.
- "loop"    - Loops the current queue.
- "seek"    - Seeks through the queue.

---

Now that the actual info about the functionality of this thing is out of the way, its storytime!

The music structure

Originally, I, keanucode, aimed to port the music structure of TravBot-v2 to this version.

This would have been much too difficult of a task for three main reasons:

1. The original code is written badly.
2. The original code is written by another person.
3. The original code is written in JS.

These three reasons make porting the structure considerably harder.

So, of course, I resorted to different matters. I present: discord.js-lavalink-musicbot. (npmjs.org)

This pre-built module utilises Lavalink, which is an audio sending node based on Lavaplayer and JDA-Audio.

I've previously considered using Lavalink, but it turned out to be more difficult for me to implement than I thought.

So, I tried again with discord.js-lavalink-musicbot.

ahem...

The library was written in such a way that it didn't work!

---

Fixing the broken library

First off; in the library's interface LavaLinkNodeOptions, option id was a required option:

interface LavalinkNodeOptions {
    host: string;
    id: string;
    /* ... */
}

Here's the catch. id was referenced nowhere in the library code. It was literally useless.

So, I lazily removed that by adding a ? to the parameter. (id?:)

Next up:

declare function LavalinkMusic(client: Client, options: MusicbotOptions) {}

First up, the TS compiler reports that: An implementation cannot be declared in ambient contexts. ts(1183)

Secondly, this function, which makes up the entirety of the library, explicitly returns an any type. As you can see, the declared function returns... no specific type.

So, that had to be changed to:

- declare function LavalinkMusic(client: Client, options: MusicbotOptions) {}
+ declare function LavalinkMusic(client: Client, options: MusicbotOptions): any

...next up:

try {
const res = await axios.get(
    /* ... */
    `https://${music.lavalink.restnode.host}:`
    /* ... */
)

The library tries to fetch the URL of the Lavalink node. With HTTPS.

I think you can see where this is going. An SSL error.

Changed the https to http, and all is well.

I republished the library under the name "discord.js-lavalink-lib" so I can easily install the non-broken version.

---

Implementing the functionality

There's nothing much to do there, honestly. Only one edit to the original snippet has to be made.

The original example snippet has the following:

const Discord = require('discord.js');
const client = new Discord.Client();
client.music = new (require('discord.js-lavalink-musicbot'))(client, {
    /* ...config... */
});

As you can see, this is... kind of disgusting. And on top of that, incompatible with TS.

So, we have to change a few things. First off, since TS is strict, it'll tell you that music doesn't exist on client. Which is true. The Client class has no music property.

So, we make client. an any type using keyword as:

const Discord = require('discord.js');
const client = new Discord.Client();
(client as any).music = LavalinkMusic(client, {
  /* ...config... */
});

And that's about it. Launch up Lavalink, and start the bot.