bin/express-cli.js
function emptyDirectory (dir, fn) {
  fs.readdir(dir, function (err, files) {
    if (err && err.code !== 'ENOENT') throw err
    fn(!files || !files.length)
  })
}
function emptyDirectory (dir, fn) {
  fs.readdir(dir, function (err, files) {
    if (err && err.code !== 'ENOENT') throw err
    fn(!files || !files.length)
  })
}
Check if the given directory `dir` is empty.

@param {String} dir
@param {Function} fn