config.json

{
    "foo": "/path/to/foo"
  , "bar": "/path/to/bar"
}

hash.js

module.exports = hash
 
//  hash := (tasks:Object<String, Continuable<T>>)
//      => Continuable<Object<String, T>>
function hash(tasks) {
    return function continuable(callback) {
        var result = {}
        var ended = false
        var count = 0
        var keys = Object.keys(tasks)
        var length = keys.length
 
        keys.forEach(function (key) {
            var source = tasks[key]
 
            source(function (err, value) {
                if (err && !ended) {
                    callback(err)
                } else if (!err) {
                    result[key] = value
                    if (++count === length) {
                        callback(null, result)
                    }
                }
            })
        })
    }
}

index.js

var fs = require("fs")
var map = require("continuable/map")
var hash =  require("./hash")

function stat (uri) {
  return function continuable (callback) {
    fs.stat(uri, callback)
  }
}

function loadFiles(files, root, config) {
  var uris = files.reduce(function (acc, key) {
    acc[key] = path.resolve(root, config[key])
    return acc
  }, {})
  
  var stats = Object.keys(uris).reduce(function (acc, key) {
    return map(function (stat) {
      return { stat: stat, uri: uris[key] }
    })(stat(uris[key]))
  })
  
  return hash(stats)
}

// MAIN function, load a config given a root directory and a config
// object

loadFiles(["foo", "bar"])(function (err, result) {
  if (err) return console.error('Error:', err)
  console.log(result)
})

resuilt.js

// expected result:

{ foo: 
   { stat: 
      { dev: 2065,
        mode: 16893,
        nlink: 2,
        uid: 1000,
        gid: 1000,
        rdev: 0,
        blksize: 4096,
        ino: 11701430,
        size: 4096,
        blocks: 8,
        atime: Tue Apr 30 2013 14:49:26 GMT+1000 (EST),
        mtime: Tue Apr 30 2013 14:49:26 GMT+1000 (EST),
        ctime: Tue Apr 30 2013 14:49:26 GMT+1000 (EST) },
     uri: '/path/to/foo' },
  bar: 
   { stat: 
      { dev: 2065,
        mode: 16893,
        nlink: 2,
        uid: 1000,
        gid: 1000,
        rdev: 0,
        blksize: 4096,
        ino: 11817511,
        size: 4096,
        blocks: 8,
        atime: Tue Apr 30 2013 14:49:33 GMT+1000 (EST),
        mtime: Tue Apr 30 2013 14:49:33 GMT+1000 (EST),
        ctime: Tue Apr 30 2013 14:49:33 GMT+1000 (EST) },
     uri: '/path/to/bar' } }