test.js

var fs = require('fs');

function read_directory(path, next) {
    fs.readdir(path, function (err, files) {
        console.log('Files in '+path);
        var count = files.length,
            results = {};
        files.forEach(function (filename) {
            fs.readFile(filename, function (data) {
                console.log('-'+filename);
                results[filename] = data;
                count--;
                if (count <= 0) {
                    next(results);
                }
            });
        });
    });
}

function read_directories(paths, next) {
    var count = paths.length,
        data = {};
    paths.forEach(function (path) {
        read_directory(path, function (results) {
            data[path] = results;
            count--;
            if (count <= 0) {
                next(data);
            }
        });
    });
}

read_directories(['tmpDir', 'public'], function (data) {
});