var readdirrsync = require('readdirrsync');
 
var dirStructure = readdirRSync(__dirname + '/testdir'); // return type: Array
/* dirStructure:
[ '/Users/jb/Developing/readdirRSync/test/testdir/file1.txt',
  '/Users/jb/Developing/readdirRSync/test/testdir/file2.txt',
  '/Users/jb/Developing/readdirRSync/test/testdir/file3.txt',
  '/Users/jb/Developing/readdirRSync/test/testdir/subdir/file4.txt' ]
*/

var readdirrsync = require('readdirrsync');
var crypto       = require('crypto');
var hash         = crypto.createHash('md5');
var files        = readdirrsync(dirname);
 
for (var i in files) {
  hash.update(fs.readFileSync(files[i]));
}
 
console.log(hash.digest('hex'));