I can't make a Node JS timer, how to do it?

Question

Node.js

in general, the essence of the script is as follows, it must respond in a conversation to the messages of the user whose ID is indicated in the script with text from a text document. I was able to implement this, but I can’t make a timer for the answer, for example, a person wrote any word and the bot should answer him after a certain time and not immediately or randomly in time to pretend as if a person is writing (something like an answering machine) help me do it, I will be grateful))) And if you also help to make it look like a person prints using the messages.setActivity method, then you will not have a price))

const { VK, keyboard } = require('vk-io');
const vk = new VK();
const rq = require("prequest");
const { api } = vk;
const fs = require("fs");
const acc = require("./base/acc.json");

var ls_arr = fs.readFileSync('ls.txt').toString().split("\n");


vk.setOptions({ token: 'сюда токен'});
const { updates, snippets } = vk;

updates.startPolling();
console.log(`Хелло Ворлд`)

updates.on('message', async (message) => {
  if(message.senderId == 581661789) return;
  var a = message.senderId;
    if(a == сюда айди жертвы без скобок)
    {
        acc.ls++;
  console.log(acc.ls);
  return message.reply(ls_arr[acc.ls%ls_arr.length]);

}
});

setInterval(function(){
  fs.writeFileSync("./base/acc.json", JSON.stringify(acc, null, "\t")) 
}, 3500);

Answer 1

Before sending, call the api method messages.setActivity, which will last 10 seconds.
Further:

setTimeout(() => {
  message.reply("Ответ");
}, Math.floor(Math.random() * Math.floor(10))); // Рандомное число от 0 до 10

It is also not clear why you make an interval of 3.5 seconds in which you write synchronously to json, it is better to write asynchronously and after each message, or after every N messages.