sync-files
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Synchronize files or folders locally, with a watch option
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# Chokidar [](https://travis-ci.org/paulmillr/chokidar) [](https://ci.appveyor.com/project/es128/chokidar/branch/master) [](https://coveralls.io/r/paulmillr/chokidar)
A neat wrapper around node.js fs.watch / fs.watchFile / fsevents.
[](https://nodei.co/npm/chokidar/)
[](https://nodei.co/npm/chokidar/)
#### [See what's new in v1.0](https://github.com/paulmillr/chokidar/blob/master/CHANGELOG.md#chokidar-100-rc1-21-january-2015)
## Why?
Node.js `fs.watch`:
* Doesn't report filenames on OS X.
* Doesn't report events at all when using editors like Sublime on OS X.
* Often reports events twice.
* Emits most changes as `rename`.
* Has [a lot of other issues](https://github.com/joyent/node/search?q=fs.watch&type=Issues)
* Does not provide an easy way to recursively watch file trees.
Node.js `fs.watchFile`:
* Almost as bad at event handling.
* Also does not provide any recursive watching.
* Results in high CPU utilization.
Other node.js watching libraries:
* Are not using ultra-fast non-polling fsevents watcher implementation on OS X
Chokidar resolves these problems.
It is used in
[brunch](http://brunch.io),
[karma](http://karma-runner.github.io),
[PM2](https://github.com/Unitech/PM2),
[socketstream](http://www.socketstream.org),
[derby](http://derbyjs.com/),
[watchify](https://github.com/substack/watchify),
and [many others](https://www.npmjs.org/browse/depended/chokidar/).
It has proven itself in production environments.
## Getting started
Install chokidar via node.js package manager:
npm install chokidar
Then just require the package in your code:
```javascript
var chokidar = require('chokidar');
var watcher = chokidar.watch('file, dir, or glob', {
ignored: /[\/\\]\./, persistent: true
});
var log = console.log.bind(console);
watcher
.on('add', function(path) { log('File', path, 'has been added'); })
.on('addDir', function(path) { log('Directory', path, 'has been added'); })
.on('change', function(path) { log('File', path, 'has been changed'); })
.on('unlink', function(path) { log('File', path, 'has been removed'); })
.on('unlinkDir', function(path) { log('Directory', path, 'has been removed'); })
.on('error', function(error) { log('Error happened', error); })
.on('ready', function() { log('Initial scan complete. Ready for changes.'); })
.on('raw', function(event, path, details) { log('Raw event info:', event, path, details); })
// 'add', 'addDir' and 'change' events also receive stat() results as second
// argument when available: http://nodejs.org/api/fs.html#fs_class_fs_stats
watcher.on('change', function(path, stats) {
if (stats) console.log('File', path, 'changed size to', stats.size);
});
// Watch new files.
watcher.add('new-file');
watcher.add(['new-file-2', 'new-file-3', '**/other-file*']);
// Un-watch some files.
watcher.unwatch('new-file*');
// Only needed if watching is `persistent: true`.
watcher.close();
// One-liner
require('chokidar').watch('.', {ignored: /[\/\\]\./}).on('all', function(event, path) {
console.log(event, path);
});
```
## API
`chokidar.watch(paths, options)` — takes one or more paths (which may be paths to files,
dirs to be watched recursively, or glob patterns) and options:
#### Persistence
* `persistent` (default: `true`). Indicates whether the process
should continue to run as long as files are being watched. If set to
`false` when using `fsevents` to watch, no more events will be emitted
after `ready`, even if the process continues to run.
#### Path filtering
* `ignored` ([anymatch](https://github.com/es128/anymatch)-compatible definition)
Defines files/paths to be ignored. The **whole path** is tested, not just
filename. If a function with two arguments is provided, it gets called
twice per path - once with a single argument (the path), second time with
two arguments (the path and the [`fs.Stats`](http://nodejs.org/api/fs.html#fs_class_fs_stats)
object of that path).
* `ignoreInitial` (default: `false`). Indicates whether chokidar
should ignore the initial `add` events or not.
* `followSymlinks` (default: `true`). When `false`, only the
symlinks themselves will be watched for changes instead of following
the link references and bubbling events through the link's path.
* `cwd` (no default). The base directory from which watch `paths` are to be
derived. Paths emitted with events will be relative to this.
#### Performance
* `interval` (default: `100`). Interval of file system polling.
* `binaryInterval` (default: `300`). Interval of file system
polling for binary files (see extensions in src/is-binary).
* `usePolling` (default: `false`).
Whether to use fs.watchFile (backed by polling), or fs.watch. If polling
leads to high CPU utilization, consider setting this to `false`. Polling
may be necessary to successfully watch files in certain situation, such as
network mounted drives. Setting to `true` explicitly on OS X overrides the
`useFsEvents` default.
* `useFsEvents` (default: `true` on OS X). Whether to use the
`fsevents` watching interface if available. When set to `true` explicitly
and `fsevents` is available this supercedes the `usePolling` setting. When
set to `false` on OS X, `usePolling: true` becomes the default.
* `alwaysStat` (default: `false`). If relying upon the
[`fs.Stats`](http://nodejs.org/api/fs.html#fs_class_fs_stats)
object that may get passed with `add`, `addDir`, and `change` events, set
this to `true` to ensure it is provided even in cases where it wasn't
already available from the underlying watch events.
* `depth` (default: `undefined`). If set, limits how many levels of
subdirectories will be traversed.
#### Errors
* `ignorePermissionErrors` (default: `false`). Indicates
whether to watch files that don't have read permissions.
* `atomic` (default: `true` if `useFsEvents` and `usePolling` are `false`).
Automatically filters out artifacts that occur when using editors that use
"atomic writes" instead of writing directly to the source file.
### Methods & Events
`chokidar.watch()` produces an instance of `FSWatcher`. Methods of `FSWatcher`:
* `.add(path / paths)`: Add files, directories, or glob patterns for tracking.
Takes an array of strings or just one string.
* `.on(event, callback)`: Listen for an FS event.
Available events: `add`, `addDir`, `change`, `unlink`, `unlinkDir`, `ready`, `raw`, `error`.
Additionally `all` is available which gets emitted with the underlying event name
and path for every event other than `ready`, `raw`, and `error`.
* `.unwatch(path / paths)`: Stop watching files, directories, or glob patterns.
Takes an array of strings or just one string.
* `.close()`: Removes all listeners from watched files.
## License
The MIT license.
Copyright (c) 2012 - 2015 Paul Miller (http://paulmillr.com) & Elan Shanker
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.