Cacher is the code snippet organizer for pro developers

var fs = require('fs'),
    path = require('path'),
    async = require('async');

function reduceDir(dir, mem, callback) {
  if (!callback && typeof mem === 'function') {
    callback = mem;
    mem = null;
  }
  
  var base;
  
  if (mem) {
    base = path.basename(dir);
  }
  else {
    mem = mem || {};
  }
  
  fs.readdir(dir, function (err, files) {
    if (err) {
      return callback(err);
    }
    
    async.reduce(
      files,
      mem,
      function (memo, file, next) {
        var fullpath = path.join(dir, file);
        fs.stat(fullpath, function (err, stat) {
          if (err) {
            return err.code !== 'ENOENT'
              ? next(err)
              : next();
          }

          if (base) {
            mem[base] = mem[base] || {};
            
            if (stat.isDirectory()) {
              return reduceDir(fullpath, mem[base], function (err, subtree) {
                return next(null, mem);
              });
            }
            else {
              mem[base][file] = null;
            }
          }
          else {
            if (stat.isDirectory()) {
              mem[file] = {};
              return reduceDir(fullpath, mem[file], function (err, subtree) {
                return next(null, mem);
              });              
            }
            else {
              mem[file] = null;
            }
          }

          next(null, mem);
        });
      },
      function (err, result) {
        return err
          ? callback(err)
          : callback(null, result);
      }
    );
  });
}