index.js

const Discord = require('discord.js');
const client = new Discord.Client();

client.on('ready', () => {
  console.log(`Logged in as ${client.user.tag}!`);
});

client.on('message', msg => {
  if (msg.content === 'ping') {
    msg.reply('Pong!');
  }
  if (message.content === 'what is my avatar') {
    // Send the user's avatar URL
    message.reply(message.author.avatarURL);
  }
});
if (message.content.startsWith('!kick')) {
    // Assuming we mention someone in the message, this will return the user
    // Read more about mentions over at https://discord.js.org/#/docs/main/stable/class/MessageMentions
    const user = message.mentions.users.first();
    // If we have a user mentioned
    if (user) {
      // Now we get the member from the user
      const member = message.guild.member(user);
      // If the member is in the guild
      if (member) {
        /**
         * Kick the member
         * Make sure you run this on a member, not a user!
         * There are big differences between a user and a member
         */
        member.kick('Optional reason that will display in the audit logs').then(() => {
          // We let the message author know we were able to kick the person
          message.reply(`Successfully kicked ${user.tag}`);
        }).catch(err => {
          // An error happened
          // This is generally due to the bot not being able to kick the member,
          // either due to missing permissions or role hierarchy
          message.reply('I was unable to kick the member');
          // Log the error
          console.error(err);
        });
      } else {
        // The mentioned user isn't in this guild
        message.reply('That user isn\'t in this guild!');
      }
    // Otherwise, if no user was mentioned
    } else {
      message.reply('You didn\'t mention the user to kick!');
    }
  }
});

client.login('token');