Discord.js | Cannot read property 'displayName' of undefined - discord

Question

I am making a discord bot for a friend and everything worked until i tried to make an unban command. when i tried to unban someone it did not work. then i looked at the error. it displayed:
TypeError: Cannot read property 'displayName' of undefined
at C:\Users\user\folder_name\commands\unban.js:37:67
at processTicksAndRejections (internal/process/task_queues.js:97:5)
Unhandled promise rejection: TypeError: Cannot read property 'displayName' of undefined
at C:\Users\user\folder_name\commands\unban.js:37:67
at processTicksAndRejections (internal/process/task_queues.js:97:5)
this is my code
const Discord = require('discord.js');
module.exports = {
name: 'unban',
description: 'unban user',
aliases: [],
cooldown: 0,
args: true,
usage: '<mention> [reason]',
guildOnly: true,
execute(message, args, client) {
console.log(message.content);
const embedMsg = new Discord.RichEmbed()
.setColor('#0000ff')
.setAuthor(message.author.username, message.author.displayAvatarURL)
.setThumbnail(message.author.displayAvatarURL)
.setTimestamp()
.setFooter('botname', client.user.displayAvatarURL);
let member = message.mentions.members.first();
if (!message.member.hasPermission('BAN_MEMBERS')) {
embedMsg.setDescription(`You don't have permission to unban!`);
return message.channel.send(embedMsg);
}
if (!args.length >= 1) {
embedMsg.setDescription('^unban takes at least one argument! the proper usage is ^unban <mention> [reason]');
message.channel.send(embedMsg);
}
if (args.length < 2) {
message.guild.unban(member).then(() => {
embedMsg.setDescription(`${member.displayName} has been succesfully unbanned`);
return message.channel.send(embedMsg);
}).catch((err) => {
embedMsg.setDescription(`Could not unban ${member.displayName}`);
console.log(err);
return message.channel.send(embedMsg);
});
return;
}
newargs = "";
for (var i = 1; i < args.length; i++) {
newargs += (args[i] + " ");
}
message.guild.unban(member).then(() => {
embedMsg.setDescription(`${member.displayName} has been succesfully unbanned for reason ${newargs}`);
return message.channel.send(embedMsg);
}).catch((err) => {
embedMsg.setDescription(`Could not unban ${member.displayName}`);
console.log(err);
return message.channel.send(embedMsg);
});
return;
}
}
does anyone know what i am doing wrong?

Answer 1

It says in the discord.js's official docs that the unban method returns a member object https://discord.js.org/#/docs/main/stable/class/Guild?scrollTo=unban
The reason why it says 'undefined' is because the member object you are trying to access is not in the server/guild. So, therefore you need add a reference to the member object that the method returns:
message.guild.unban('some user ID').then((member) => {
embedMsg.setDescription(`${member.username} has been succesfully unbanned for reason ${newargs}`);
return message.channel.send(embedMsg);
}

Answer 2

Unbun method return a user promise, so user dont have property displayName, you need use .username
And you can use user.id for unban, so right way will be let member = message.mentions.members.first() || args[0]
This check doing wrong, because its not stop code execute
if (!args.length < 2) {
embedMsg.setDescription('^unban takes at least one argument! the proper usage is ^unban <mention> [reason]');
return message.channel.send(embedMsg);
}
Amm and whats this part code doing? Why its duplicate?
if (args.length < 2) {
message.guild.unban(member)
.then(() => {
embedMsg.setDescription(`${member.username} has been succesfully unbanned`);
return message.channel.send(embedMsg);
})
.catch((err) => {
embedMsg.setDescription(`Could not unban ${member.username}`);
console.log(err);
return message.channel.send(embedMsg);
});
return;
}
The edited code
const Discord = require('discord.js');
module.exports = {
name: 'unban',
description: 'unban user',
aliases: [],
cooldown: 0,
args: true,
usage: '<mention> [reason]',
guildOnly: true,
execute(message, args, client) {
const embedMsg = new Discord.RichEmbed()
.setColor('#0000ff')
.setAuthor(message.author.username, message.author.displayAvatarURL)
.setThumbnail(message.author.displayAvatarURL)
.setTimestamp()
.setFooter('botname', client.user.displayAvatarURL);
let member = message.mentions.members.first() || args[0]
if (!message.member.hasPermission('BAN_MEMBERS')) {
embedMsg.setDescription(`You don't have permission to unban!`);
return message.channel.send(embedMsg);
}
if (!args.length < 2) {
embedMsg.setDescription('^unban takes at least one argument! the proper usage is ^unban <mention> [reason]');
return message.channel.send(embedMsg);
}
let newargs = args.splice(1,args.length).join(' ')
message.guild.unban(member)
.then(() => {
embedMsg.setDescription(`${member.username} has been succesfully unbanned for reason ${newargs}`);
return message.channel.send(embedMsg);
})
.catch((err) => {
embedMsg.setDescription(`Could not unban ${member.username}`);
console.log(err);
return message.channel.send(embedMsg);
});
}
}