update-username-cache.js

const flatCache = require('flat-cache');
const cache = flatCache.load('userCache8');

module.exports = function (client){
    let guild = client.guilds.cache.get("803429347750576138");
	try{
	guild.members.cache.forEach(function (m){
		let oldUsernames = cache.getKey(m.user.id)
		// console.log(oldUsernames)
		if(cache.getKey(m.user.id) === undefined){
			
			cache.setKey(m.user.id, [{user: m.user.username, date: Date()}])
			let newUsername = cache.getKey(m.user.id)[0].user
			console.log(`NEW...${newUsername}`);
			
		}
		else if(oldUsernames[0].user !== m.user.username){
			oldUsernames.unshift({user: m.user.username, date: Date()})
			let previousUsername = cache.getKey(m.user.id)[1].user
			cache.setKey(m.user.id, oldUsernames)
			let newUsername = cache.getKey(m.user.id)[0].user
			console.log(`CHANGED...${newUsername}`);
			const channel = guild.channels.cache.get('831411449426477057');
  			channel.send(`CHANGED: ${previousUsername} is now ${newUsername}`);
		}
		else{
			let allNames = cache.getKey(m.user.id);
			for(let i = 0; i < allNames.length; i++){
				console.log(allNames[i].user);
			}
			console.log(`old...${oldUsernames[0].user}`);
		}
	})
	console.log('Cache complete');
	// console.log(cache.all())
	cache.save()
	} catch (error) {
		console.error(error);
    }
}