promises...

gistfile1.txt

var Promise = require("bluebird");
var fs = require("fs");
Promise.promisifyAll(fs);

// fs.readFileAsync("file.js", "utf8").then(...)

var readFileTree = function ( root ) {

  var results = [];

  return new Promise( function ( resolve, reject ) {
  
    // do stuff
    // do stuff
    
    if (done) {
      resolve( results ) 
    } else {
      repeat
    }
  
  })

}

readFileTree().then( function (results) {
  //
})