How to declare a guild for a bot yourself?

Question

Node.js

There is one bot code. It is necessary that it checks for the presence of the user on the server. I tried to announce the server through its id, but it didn't work... You won't be able to receive it through the message, because the message is in the bot's personal.
Here is the code itself, but I don't think it can help in this matter:

//Объявление разной дичи
const Discord = require('discord.js');

const bot = new Discord.Client;

console.log('Анонимный чат готов к работе.')

const {
  token,
  webhokID,
  webhookTK,
  sishookTK,
  sishokID} = require('./config.json');

const hook = new Discord.WebhookClient(webhokID, webhookTK);

const sisHook = new Discord.WebhookClient(sishokID, sishookTK);

//Системные сообщения
bot.on('ready', () =>{
sisHook.send('Бот полностью готов функционировать и приносить радость!')
});
bot.on('error', () =>{
  sisHook.send("Что-то сломалось... почините меня...\n" + error)
});

//код
bot.on('message', message => {
  if(message.author === bot.user) return;
  if(message.content.startsWith('/') && message.channel.type == "dm") {
  message.content = message.content.replace("/","")
  hook.send(message.content);
  console.log(message.author + " сказал " + '"' + message.content + '"')
  
  }
});

//Ну, это понятно всем...
bot.login(token);

If there are any other errors, then I apologize: I wrote for the first time an under-samopis.

Answer 1

1. Collect the IDs of all server users in an array:

let arr = [];
message.guild.members.cache.forEach(u => arr.push(u.id))

2. using the method.includes, check the array for the presence of a specific user:

if (arr.includes("id_пользователя") === true) {
  ...
} else {
  ...
}