node-walk
====

A port python's `os.walk`, but using Node.JS conventions.

  * EventEmitter
  * Asynchronous
  * Chronological (optionally)
  * Built-in flow-control

As few file descriptors are opened at a time as possible.
This is particularly well suited for single hard disks which are not flash or solid state.

Memory usage is high (120mb for 60,000 dirs), but reduction is being investigated.
Patches welcome.

Installation
----

    npm install walk

Usage
====

    var walk = require('walk').walk,
      options,
      walker;

    options = {
        followLinks: false,
    };

    walker = walk("path/to/dir", options);

    walker.on("directories", function (root, dirStatsArray, next) {
      // dirStatsArray is an array of `stat` objects with the additional attributes
      // * type
      // * error
      // * name
      
      next();
    });

    walker.on("file", function (root, fileStats, next) {
      fs.readFile(file, function () {
        // doStuff
        next();
      });
    });

    walker.on("errors", function (root, nodeStatsArray, next) {
      next();
    });

    walker.on("end", function () {
      console.log("all done");
    });

API
====

Emitted Values

  * `root` - the containing the files to be inspected
  * *stats[Array]* - a single `stats` object or an array with some added attributes
    * type - 'file', 'directory', etc
    * error
    * name - the name of the file, dir, etc 
  * next - no more files will be read until this is called

Single Events - fired immediately

  * `end` - No files, dirs, etc left to inspect

  * `directoryError` - Error when `fstat` succeeded, but reading path failed (Probably due to permissions).
  * `node` - a `stats` object for a node of any type
  * `file` - includes links when `followLinks` is `true`
  * `directory`
  * `blockDevice`
  * `characterDevice`
  * `symbolicLink` - always empty when `followLinks` is `true`
  * `FIFO`
  * `socket`

Events with Array Arguments - fired after all files in the dir have been `stat`ed

  * `errors` - errors encountered by `fs.stat` when reading ndes in a directory
  * `nodes` - an array of `stats` of any type
  * `files`
  * `directories` - modification of this array - sorting, removing, etc - affects traversal
  * `blockDevices`
  * `characterDevices`
  * `symbolicLinks`
  * `FIFOs`
  * `sockets`

**Warning** beware of infinite loops when `followLinks` is true.

Comparisons
====

Tested on my `/System` containing 59,490 (+ self) directories (and lots of files).
The size of the text output was 6mb.

`find`:
    time bash -c "find /System -type d | wc"
    59491   97935 6262916

    real  2m27.114s
    user  0m1.193s
    sys 0m14.859s

`find.js`:

Note that `find.js` omits the start directory

    time bash -c "node examples/find.js /System -type d | wc"
    59490   97934 6262908
   
    # Test 1 
    real  2m52.273s
    user  0m20.374s
    sys 0m27.800s
    
    # Test 2
    real  2m23.725s
    user  0m18.019s
    sys 0m23.202s

    # Test 3
    real  2m50.077s
    user  0m17.661s
    sys 0m24.008s