Answers for "discord js bot amount of servers join"

how to see in how many servers your discord bot is d.js

You need to use client.setActivity() and then use the client.guilds.cache.size value. 
For example:

client.setActivity(`Currently in ${client.guilds.cache.size} servers`);

how to display server count on discord.js

module.exports.run = async (client, message, arguments) => {
   const guild = client.guilds.get("566596189827629066");
   setInterval(function () {
      var memberCount = guild.members.filter(member => !member.user.bot).size;  
      var memberCountChannel = client.channels.get("626462657817477131");
      memberCountChannel.setName(`${guild.name} has ${memberCount} members!`);
   }, 1000);
};