getFileTree.js

var fs = require('fs');

/**
 * Asynchronously build a tree corresponding to the specified directory.
 *
 * @param dir Root directory.
 * @param cb  Callback function with (err, tree) signature.
 */
function getFileTree(dir, cb) {
    var results = {}; 
    fs.readdir(dir, function(err, list) {
        if (err) {
            return cb(err);
        }   
        var remaining = list.length;
        if (!remaining) {
            return cb(null, results);
        }   
        list.forEach(function(file) {
            var fullpath = dir + '/' + file,
                addIt = function(err, res) {
                    results[file] = res;
                    if (--remaining === 0) {
                        cb(null, results);
                    }   
                };  
            fs.stat(fullpath, function(err, stat) {
                if (stat && stat.isDirectory()) {
                    getFileTree(fullpath, addIt);
                } else {
                    addIt(null, null);
                }   
            }); 
        }); 
    }); 
};