code: function saveDirs(path, obj, cb) {
    var currDir = ''
    var root    = ''
  
    walk.walk(path, walkFn, function(err) {
      if (err) return cb(err)
      cb(null, obj)
    })
  
    function walkFn(baseDir, filename, stat, next) {
      if (!root) root = baseDir
      baseDir = stripLeadingSlash(baseDir.split(root)[1])
  
      if (!baseDir) return next()
      if (obj[baseDir]) return next()
  
      if (baseDir != currDir) currDir = baseDir
  
      if (stat.isDirectory()) {
        setObject(baseDir, obj, {})
        return next()
      }
  
      setObject(baseDir, obj, [])
      next()
    }
  }
docs: Save directory structure. @param {String} path @param {Object} obj @param {Function} cb