series.js

var fs = require('fs')
var Q = require('q')
var fs_stat = Q.denodeify(fs.stat)

var files = ['./fixtures/file1', './fixtures/file2', './fixtures/file3']

function getStatsSeries (files) {
  var d = Q.defer()
  var results = []
  files.reduce(function (last, file) {
    return last.then(function (stat) { results.push(stat); return fs_stat(file) })
  }, Q())
  .then(function (lastStat) {
    results.shift() // first result is the initialVal for the reduce (garbage)
    results.push(lastStat) // last result happens in this promise
    d.resolve(results)
  }, d.reject)
  return d.promise
}

getStatsSeries(files).then(console.log, console.error)