Discord.js meninggalkan guild

// If you have guild defined
// eg, message.guild
guild.leave()
	.catch(console.log) // If anything goes wrong

// Or,
client.guilds.cache.get("PUT_GUILD_ID_HERE").leave()
// If guild isn't cached
client.guilds.fetch("GUILD_ID")
	.then(guild => guild.leave())
OIIA