node_recursive_dir_reader.js

function filewalker(dir, done) {
    let results = [];

    fs.readdir(dir, function (err, list) {
        if (err) return done(err);

        var pending = list.length;

        if (!pending) return done(null, results);

        list.forEach(function (file) {
            file = path.resolve(dir, file);

            fs.stat(file, function (err, stat) {
                // If directory, execute a recursive call
                if (stat && stat.isDirectory()) {
                    // Add directory to array [comment if you need to remove the directories from the array]
                    //results.push(file);

                    filewalker(file, function (err, res) {
                        //path.relative(__dirname + "/uploads", res)
                        results = results.concat(res);
                        if (!--pending) done(null, results);
                    });
                } else {
                    results.push(file);

                    if (!--pending) done(null, results);
                }
            });
        });
    });
};

readdirSync_example.js

var getFileData = function (dir) {
    var result = [];
    fs.readdirSync(dir).forEach(function (file) {

        var stat = fs.statSync(dir + "/" + file);

        if (stat && stat.isFile()) {
            result.push(file);
        }
    });
    return result;
};