Iterate all the files

fileIterator.js

var fs = require("fs"),
    path = require("path");

function iterateFiles(uri, callback, done, fileRegexp) {
    var counter = 1
    fs.readdir(uri, errorProxy(done, readFiles))

    function readFiles(err, files) {
        counter += files.length
        files.forEach(isDirOrFile)
        next()
    }

    function isDirOrFile(fileName) {
        fileName = path.join(uri, fileName)

        fs.stat(fileName, errorProxy(done, readOrRecurse))

        function readOrRecurse(err, stat) {
            if (stat.isDirectory()) {
                iterateFiles(fileName, callback, errorProxy(done, next), fileRegexp)
            } else if (stat.isFile() && (!fileRegexp || fileRegexp.test(fileName))) {
                callback(fileName)
                next()
            } else {
                next()
            }
        }
    }

    function next() {
        if (--counter === 0) {
            done(null)
        }
    }
}

function errorProxy(errorHandler, callback) {
    return proxy

    function proxy(err) {
        if (err) {
            return errorHandler(err)
        }
        return callback.apply(this, arguments)
    }
}

usage.js

var iterateFiles = require("fileIterator"),
    path = require("path")

// Load all javascript files in the test folder or any of their sub folders
iterateFiles(path.join(process.cwd(), "./test"), function (fileName) {
    // run code for each recursively found js file
}, function (err) {
    // run code when all files have been found recursively
}, /.js$/)

Updated not to default to .js but simply allow all files.