Chokidar

A neat wrapper around node.js fs.watch / fs.watchFile.

Why?

Node.js fs.watch:

• Doesn't report filenames on mac.
• Doesn't report events at all when using editors like TextMate2 on mac.
• Sometimes report events twice.
• Has only one non-useful event: rename.
• Has a lot of other issues

Node.js fs.watchFile:

• Almost as shitty in event tracking.

Chokidar resolves this problems.

It is used in brunch, socketstream, and karma and had proven itself in production env.

Getting started

Install chokidar via node.js package manager:

npm install chokidar

Then just require the package in your code:

var chokidar = require('chokidar');

var watcher = chokidar.watch('file or dir', {ignored: /^\./, persistent: true});

watcher
  .on('add', function(path) {console.log('File', path, 'has been added');})
  .on('change', function(path) {console.log('File', path, 'has been changed');})
  .on('unlink', function(path) {console.log('File', path, 'has been removed');})
  .on('error', function(error) {console.error('Error happened', error);})

// 'add' and 'change' events also receive stat() results as second argument.
// http://nodejs.org/api/fs.html#fs_class_fs_stats
watcher.on('change', function(path, stats) {
  console.log('File', path, 'changed size to', stats.size);
});

watcher.add('new-file');
watcher.add(['new-file-2', 'new-file-3']);

// Only needed if watching is persistent.
watcher.close();

API

• chokidar.watch(paths, options): takes paths to be watched and options:
  • options.ignored (regexp or function) files to be ignored. Example: chokidar.watch('file', {ignored: /^\./}).
  • options.persistent (default: false). Indicates whether the process should continue to run as long as files are being watched.
  • options.ignorePermissionErrors (default: false). Indicates whether to watch files that don't have read permissions or not.
  • options.ignoreInitial (default: false). Indicates whether chokidar should ignore initial add events or not.
  • options.interval (default: 100). Interval of file system polling.
  • options.binaryInterval (default: 300). Interval of file system polling for binary files (see extensions in src/is-binary).

chokidar.watch() produces an instance of FSWatcher. Methods of FSWatcher:

• .add(file / files): add directories / files for tracking. Takes an array of strings (file paths) or just one path.
• .on(event, callback): listen for an FS event. Available events: add, change, unlink, error. Also, all is available which emitted for every add, change and unlink.
• .close(): remove all listeners from watched files.

License

The MIT license.

Copyright (c) 2013 Paul Miller (http://paulmillr.com)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.