Security News
Highlights from the 2024 Rails Community Survey
A record 2,709 developers participated in the 2024 Ruby on Rails Community Survey, revealing key tools, practices, and trends shaping the Rails ecosystem.
The chokidar npm package is a file watching library that provides an efficient way to watch files and directories for changes. It is built on top of Node.js's native 'fs' module and uses native file system events where possible, but can also fall back to polling if necessary. It is designed to be cross-platform and works on macOS, Windows, and Linux.
File Watching
This feature allows you to watch files and directories for changes. The 'add' event is emitted when a file is added to the watched directory, 'change' when a file is changed, and 'unlink' when a file is removed.
const chokidar = require('chokidar');
const watcher = chokidar.watch('/path/to/dir', {ignored: /(^|[\/\\])\../});
watcher.on('add', path => console.log(`File ${path} has been added`));
watcher.on('change', path => console.log(`File ${path} has been changed`));
watcher.on('unlink', path => console.log(`File ${path} has been removed`));
Directory Watching
const chokidar = require('chokidar');
const watcher = chokidar.watch('/path/to/dir', {ignored: /^\
A neat wrapper around node.js fs.watch / fs.watchFile / fsevents.
Node.js fs.watch
:
rename
.Node.js fs.watchFile
:
Other node.js watching libraries:
Chokidar resolves these problems.
It is used in brunch, karma, PM2, browserify, webpack, BrowserSync, socketstream, derby, and many others. It has proven itself in production environments.
Install chokidar via node.js package manager:
npm install chokidar
Then just require the package in your code:
var chokidar = require('chokidar');
// One-liner for current directory, ignores .dotfiles
chokidar.watch('.', {ignored: /[\/\\]\./}).on('all', function(event, path) {
console.log(event, path);
});
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('change', function(path) { log('File', path, 'has been changed'); })
.on('unlink', function(path) { log('File', path, 'has been removed'); })
// More events.
.on('addDir', function(path) { log('Directory', path, 'has been added'); })
.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();
// Full list of options. See below for descriptions.
chokidar.watch('file', {
persistent: true,
ignored: '*.txt',
ignoreInitial: false,
followSymlinks: true,
cwd: '.',
usePolling: true,
alwaysStat: false,
depth: undefined,
interval: 100,
ignorePermissionErrors: false,
atomic: true
});
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:
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.ignored
(anymatch-compatible definition)
Defines files/paths to be ignored. The whole relative or absolute 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
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.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
. It is
typically necessary to set this to true
to successfully watch files over
a network, and it may be necessary to successfully watch files in other
non-standard situations. 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
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.usePolling: true
)
interval
(default: 100
). Interval of file system polling.binaryInterval
(default: 300
). Interval of file system
polling for binary files.
(see list of binary extensions)ignorePermissionErrors
(default: false
). Indicates whether to watch files
that don't have read permissions if possible. If watching fails due to EPERM
or EACCES
with this set to true
, the errors will be suppressed silently.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.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.If you need a CLI interface for your file watching, check out chokidar-cli which allows you to either execute a command on each change, or get a stdio stream of change events.
npm WARN optional dep failed, continuing fsevents@n.n.n
npm
handles optional dependencies and is
not indicative of a problem. Even if accompanied by other related error messages,
Chokidar should function properly.ERR! stack Error: Python executable "python" is v3.4.1, which is not supported by gyp.
npm config set python python2.7
gyp ERR! stack Error: not found: make
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.
FAQs
Minimal and efficient cross-platform file watching library
The npm package chokidar receives a total of 40,181,544 weekly downloads. As such, chokidar popularity was classified as popular.
We found that chokidar demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
A record 2,709 developers participated in the 2024 Ruby on Rails Community Survey, revealing key tools, practices, and trends shaping the Rails ecosystem.
Security News
In 2023, data breaches surged 78% from zero-day and supply chain attacks, but developers are still buried under alerts that are unable to prevent these threats.
Security News
Solo open source maintainers face burnout and security challenges, with 60% unpaid and 60% considering quitting.