node-walk

node.js walk implementation.

This is somewhat of 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 stated

• 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