Develop Reference

JS Discord buttons error : 'Cannot send empty message'

Hi I'm making a Javascript based Discord bot, and I really wanted to implement the new Discord Buttons feature, the problem is, even using the documentation examples, I get the same error, again and again :
(node:6184) UnhandledPromiseRejectionWarning: DiscordAPIError: Cannot send an empty message
Here is the code (I am using module.exports with separated files for each commands) :
const { MessageButton } = require('discord-buttons')
module.exports = {
name: 'invite',
descritipion: 'test command',
async execute(client, message, args) {
let button = new MessageButton()
.setStyle('url')
.setURL('https://npmjs.com/discord-buttons')
.setLabel('Click me !')
await message.channel.send('Hey, I am powered by npm discord-buttons : https://npmjs.com/discord-buttons');
await message.channel.send(button);
}
}

You cannot just send a button on its own. Instead, try adding the button to the previous message so they both get sent in one message as shown below
The official documentation for this is here
// Replace these
const { MessageButton } = require('discord-buttons')
await message.channel.send('Hey, I am powered by npm discord-buttons : https://npmjs.com/discord-buttons');
await message.channel.send(button);
// With these
const { MessageButton, MessageActionRow } = require('discord-buttons')
await message.channel.send('Hey, I am powered by npm discord-buttons : https://npmjs.com/discord-buttons', {
component: new MessageActionRow().addComponent(button)
});
Also, did you forget to initialize DiscordButtons? Do it when you initialize your discord bot
// Where you initialized your discord bot
const bot = new Discord.Client()
// Add this line
require("discord-button")(bot)

How can I read config file again and update prefix for Discord bot?

I'm having some trouble coding prefix changing in my Discord bot. I've got all the basic functionality working:
The prefix is saved in a config file
The bot can write to the file and save it for later use
However, I can't seem to get the bot to use the new prefix after it's changed until I restart the bot. The config file shows that the prefix has been changed, but the bot doesn't respond to it.
So, my question is either, how can I refresh the memory so that the config is reloaded, or how can I get the bot to read my config again and use the new prefix?
Thanks!
prefix.js:
const fs = require('fs'); // node.js file system module
config = require('../config.json');
const Discord = require("discord.js");
module.exports = {
name: 'prefix', // command keyword
description: 'Changes the bot prefix', // info about command
group: 'settings', // command group (not displayed in !help [command name])
aliases: ['botprefix', 'newprefix'], // using these keywords also triggers command
usage: '[new prefix]', // how command is supposed to be used
cooldown: '1', // time command cannot be reused after it has been called
args: true, // are arguments required
execute(message, args) {
fs.exists("../config.json", function (error) {
if (error) {
console.log(error);
}
})
? fs
.readFile("../config.json", function (error) {
if (error) {
console.log(error);
}
})
.toString()
: config.prefix;
const newPrefix = args.shift().toString();
newConfig = {
token: config.token,
prefix: newPrefix,
};
fs.writeFile("config.json", JSON.stringify(newConfig, null, 2), function (
error
) {
if (error) {
console.log(error);
}
});
}
config.json:
{
"token": "token",
"prefix": "!"
}

If you want to access data via require, it won't be updated later as the function is run once at the beginnign of the project, even if you re-require it. This article can give you a bit more background on it. Basically: Always use fs.readFile and you're fine

Getting API latency inside of a commandhandler

Making a ping command for my bot,
want to show the api latency with Math.round(client.ws.ping), when I use it inside of my index.js, it works fine. When I use it inside of my ping command in my command handler, it won't work and returns to NaN.
Do I need to require something to use it?
Here is my code inside of ping.js
const Discord = require('discord.js');
const client = new Discord.Client();
const fs = require('fs');
module.exports = {
name: 'ping',
description: 'measures ping',
execute(message, args){
async function pingFunction(){
const embedPingtest = new Discord.MessageEmbed()
.setTitle('Pinging...')
.setColor(0xC1CCDE)
const msg = await message.channel.send(embedPingtest);
const embedPing = new Discord.MessageEmbed()
.setTitle('Pong!')
.setDescription("Bot Latency: ``" + Math.floor(msg.createdTimestamp - message.createdTimestamp) + " ms``\nAPI Latency: ``" + Math.round(client.ws.ping) + " ms``")
.setColor(0xC1CCDE)
console.log(apiLatency)
msg.edit(embedPing)
}
pingFunction()
}
}

This is because you create a new client instance. This one doesn't has a ping as it is not logged in so not online. I suggest you pass your old instance as function parameter, to make your code look something like:
const Discord = require('discord.js');
module.exports = {
name: 'ping',
description: 'measures ping',
execute(message, args, client) {
(async () => {
const embedPingtest = new Discord.MessageEmbed()
.setTitle('Pinging...')
.setColor(0xC1CCDE)
const msg = await message.channel.send(embedPingtest);
const embedPing = new Discord.MessageEmbed()
.setTitle('Pong!')
.setDescription("Bot Latency: ``" + Math.floor(msg.createdTimestamp - message.createdTimestamp) + " ms``\nAPI Latency: ``" + Math.round(client.ws.ping) + " ms``")
.setColor(0xC1CCDE)
console.log(apiLatency)
msg.edit(embedPing)
})();
}
}
I know most guides only make you using the structure of run(message, args) but in my bot I usually use message, args, client? (mine works different tho as I modified my module structure). This also won't throw an error in your code, as JS doesn't care how many arguments you pass or don't pass.

Instead of creating a new Discord.Client(), you could refer to Zer0's answer, or an even easier way would to just use the message object.
message has a client property, which will return the client that instantiated the message.
Instead of:
Math.round(client.ws.ping)
Use:
Math.round(message.client.ws.ping)

NodeJS - Accessing Array in Another Class File

I'm writing a NodeJS application that can do some queueing in Discord. My main includes an array called queuedPlayers and is defined in the following code:
// Define our required packages and our bot configuration
const fs = require('fs');
const config = require('./config.json');
const Discord = require('discord.js');
// Define our constant variables
const bot = new Discord.Client();
const token = config.Discord.Token;
const prefix = config.Discord.Prefix;
let queuedPlayers = [];
// This allows for us to do dynamic command creation
bot.commands = new Discord.Collection();
const commandFiles = fs.readdirSync('./commands').filter(file => file.endsWith('.js'));
for (const file of commandFiles) {
const command = require(`./commands/${file}`);
bot.commands.set(command.name, command)
}
// Event Handler for when the Bot is ready and sees a message
bot.on('message', message => {
if (!message.content.startsWith(prefix) || message.author.bot) return;
const args = message.content.slice(prefix.length).trim().split(' ');
const command = args.shift().toLowerCase();
if (!bot.commands.has(command)) return;
try {
bot.commands.get(command).execute(message, args);
} catch (error) {
console.error(error);
message.reply('There was an error trying to execute that command!');
}
});
// Start Bot Activities
bot.login(token);
I then create a command in a seperate JS file and I am trying to access the Queued Players array so that way I can add to them:
module.exports = {
name: "add",
description: "Adds a villager to the queue.",
execute(message, args, queuedPlayers) {
if (!args.length) {
return message.channel.send('No villager specified!');
}
queuedPlayers.push(args[0]);
},
};
However, it keeps telling me that it is undefined and can't read the attributes of the variable. So I'm assuming it isn't passing the array over properly. Do I have to use an exports in order to able to access it between different Javascript files? Or would it be best just to use a SQLite local instance to create and manipulate the queue as needed?

It's undefined because you aren't passing the array
Change
bot.commands.get(command).execute(message, args);
to
bot.commands.get(command).execute(message, args, queuedPlayers);

discord.js client.user.setPresence() breaks bot

My bot currently runs fine. I decided to add a 'playing ' status to it. This is the relevant code:
// Import the discord.js modules required
const Discord = require('discord.js');
// Create an instance of a Discord client
const client = new Discord.Client();
// Load config properties from 'config.json'
const config = require("./config.json");
const contest = config.contest;
// Set bots status to playing 'contest' defined in 'config.json'
client.user.setPresence({
game:{
name:contest
},
status:'online'
});
In 'config.json':
{
"contest": "Example Game"
}
When I add this, the bot no longer works, and appears offline. Any ideas?
EDIT:
Source of the information:
https://discord.js.org/#/docs/main/stable/class/ClientUser?scrollTo=setPresence
In the example section:
// Set the client user's presence
client.user.setPresence({ game: { name: 'with discord.js' }, status: 'idle' })
.then(console.log)
.catch(console.error);

You need to read the config, instead of
const config = require(...)
You need
const fs = require("fs");
const config = JSON.parse(fs.readFileSync("config.json"));
const contest = config.contest;
Then
game:{
name:contest
}

Figured it out - this needs to be placed inside an event, otherwise it's just floating code. For example, I placed this inside a
client.on('ready) event.