Get the most recently changed file in NodeJS

getMostRecent.js

var path = require('path');
var fs = require('fs');

var getMostRecent = function (dir, cb) {
	var dir = path.resolve(dir);
	var files = fs.readdir(dir, function (err, files) {
		var sorted = files.map(function(v) {
			var filepath = path.resolve(dir, v);
			return {
				name:v,
				time:fs.statSync(filepath).mtime.getTime()
			}; 
		})
		.sort(function(a, b) { return b.time - a.time; })
		.map(function(v) { return v.name; });

		if (sorted.length > 0) {
			cb(null, sorted[0]);
		} else {
			cb('Y U NO have files in this dir?');
		}
	})
}

getMostRecent('./', function (err, recent) {
	if (err) console.error(err);
	console.log(recent);
});

With Promise:

const path	= require('path');
const fs	= require('fs');
function getMostRecent(dir) {
	return new Promise((resolve, reject) => {
		dir = path.resolve(dir);
		fs.readdir(dir, (err, files) => {
			const sorted = files.map((v) => {
				const filepath = path.resolve(dir, v);
				return {
					name:v,
					time:fs.statSync(filepath).mtime.getTime()
				};
			})
				.sort((a, b) => b.time - a.time)
				.map(v => v.name);

			if (sorted.length > 0) {
				resolve(sorted[0]);
			} else {
				reject('Y U NO have files in this dir?');
			}
		});
	});
}

With the recent versions of Node.js you could also make use of fsPromises: https://nodejs.org/api/fs.html#fs_fspromises_readdir_path_options

No need to wrap it on your own anymore 🎉 🍻