Get the most recent file in a directory, Node.js

Question

Get the most recent file in a directory, Node.js

I am trying to find the most recently created file in a directory using Node.js and cannot seem to find a solution. The following code seemed to be doing the trick on one machine but on another it was just pulling a random file from the directory - as I figured it might. Basically, I need to find the newest file and ONLY that file.

var fs = require('fs'); //File System
var audioFilePath = 'C:/scanner/audio/'; //Location of recorded audio files
    var audioFile = fs.readdirSync(audioFilePath)
        .slice(-1)[0]
        .replace('.wav', '.mp3');

Many thanks!

node.js

Answer 1

this should do the trick ("dir" is the directory you use fs.readdir over to get the "files" array):

function getNewestFile(dir, files, callback) {
    if (!callback) return;
    if (!files || (files && files.length === 0)) {
        callback();
    }
    if (files.length === 1) {
        callback(files[0]);
    }
    var newest = { file: files[0] };
    var checked = 0;
    fs.stat(dir + newest.file, function(err, stats) {
        newest.mtime = stats.mtime;
        for (var i = 0; i < files.length; i++) {
            var file = files[i];
            (function(file) {
                fs.stat(file, function(err, stats) {
                    ++checked;
                    if (stats.mtime.getTime() > newest.mtime.getTime()) {
                        newest = { file : file, mtime : stats.mtime };
                    }
                    if (checked == files.length) {
                        callback(newest);
                    }
                });
            })(dir + file);
        }
    });
 }

Answer 2

Assuming availability of underscore (http://underscorejs.org/) and taking synchronous approach (which doesn't utilize the node.js strengths, but is easier to grasp):

var fs = require('fs'),
    path = require('path'),
    _ = require('underscore');

// Return only base file name without dir
function getMostRecentFileName(dir) {
    var files = fs.readdirSync(dir);

    // use underscore for max()
    return _.max(files, function (f) {
        var fullpath = path.join(dir, f);

        // ctime = creation time is used
        // replace with mtime for modification time
        return fs.statSync(fullpath).ctime;
    });
}

Answer 3

Unfortunately, I don't think the files are guaranteed to be in any particular order.

Instead, you'll need to call fs.stat (or fs.statSync) on each file to get the date it was last modified, then select the newest one once you have all of the dates.