Bot Crashed When you dont mention - discord

Question

I have this command on my bot where you can mute someone using the command g!mute where the 'user' is mentioned using #. However, if you don't mention e.g GeoGeo instead of #GeoGeo, it causes the bot to crash. I know you need to put .catch(console.error); somewhere, but I'm not sure where. Thanks in advance. The Error is
let person = message.guild.member(message.mentions.users.first() || message.guild.members.get(args[1]))
^
TypeError: message.guild.members.get is not a function
Code:
const Discord = require('discord.js');
const ms = require('ms');
module.exports = {
name: 'mute',
description: "this is mute command",
execute(message, args){
if(!message.member.roles.cache.find(r => r.name ==="Staff", "Head Staff", "Owner", "Co-Owner")) return message.channel.send(`YOU DO NOT HAVE PERMISSION TO DO THAT`)
let members = args[0];
if(!members) return message.reply("g!mute <user> <time>")
let person = message.guild.member(message.mentions.users.first() || message.guild.members.get(args[1]))
if(!person) return message.reply("That person is not in the server!");
let mainrole = message.guild.roles.cache.find(role => role.name === "Fans");
let muterole = message.guild.roles.cache.find(role => role.name === "muted");
if(!muterole) return message.reply("That role does not exist");
let time = args[1];
if(!time){
return message.reply("g!mute <user> <time>");
}
person.roles.remove(mainrole.id);
person.roles.add(muterole.id);
const embed = new Discord.MessageEmbed()
.setTitle ("Muted:")
.setDescription (`${person.user.tag} has now been muted for ${ms(ms(time))}`)
.setColor(0x01B8FF)
message.channel.send(embed);
setTimeout(function(){
person.roles.add(mainrole.id)
person.roles.remove(muterole.id)
const embed = new Discord.MessageEmbed()
.setTitle ("Muted:")
.setDescription (`${person.user.tag} has been unmuted`)
.setColor(0x01B8FF)
message.channel.send(embed);
}, ms(time));
}
}

Answer 1

When faced with an error like: TypeError: message.guild.members.get is not a function
The logical thing to do is check the docs to see that message.guild.members really has a function named get. Here's the docs: https://discord.js.org/#docs/main/stable/class/GuildMemberManager
No get. But there is a cache like you use elsewhere in the code. Just by checking over the docs you can tell that your existing code is wrong (it's outdated) and you need to use cache like you do elsewhere in your code:
message.guild.members.cache.get(args[1])