opusdev/vector-similarity-api
1
1# Chokidar [](https://github.com/paulmillr/chokidar) [](https://github.com/paulmillr/chokidar)2 3> Minimal and efficient cross-platform file watching library4 5[](https://www.npmjs.com/package/chokidar)6 7## Why?8 9Node.js `fs.watch`:10 11* Doesn't report filenames on MacOS.12* Doesn't report events at all when using editors like Sublime on MacOS.13* Often reports events twice.14* Emits most changes as `rename`.15* Does not provide an easy way to recursively watch file trees.16* Does not support recursive watching on Linux.17 18Node.js `fs.watchFile`:19 20* Almost as bad at event handling.21* Also does not provide any recursive watching.22* Results in high CPU utilization.23 24Chokidar resolves these problems.25 26Initially made for **[Brunch](https://brunch.io/)** (an ultra-swift web app build tool), it is now used in27[Microsoft's Visual Studio Code](https://github.com/microsoft/vscode),28[gulp](https://github.com/gulpjs/gulp/),29[karma](https://karma-runner.github.io/),30[PM2](https://github.com/Unitech/PM2),31[browserify](http://browserify.org/),32[webpack](https://webpack.github.io/),33[BrowserSync](https://www.browsersync.io/),34and [many others](https://www.npmjs.com/browse/depended/chokidar).35It has proven itself in production environments.36 37Version 3 is out! Check out our blog post about it: [Chokidar 3: How to save 32TB of traffic every week](https://paulmillr.com/posts/chokidar-3-save-32tb-of-traffic/)38 39## How?40 41Chokidar does still rely on the Node.js core `fs` module, but when using42`fs.watch` and `fs.watchFile` for watching, it normalizes the events it43receives, often checking for truth by getting file stats and/or dir contents.44 45On MacOS, chokidar by default uses a native extension exposing the Darwin46`FSEvents` API. This provides very efficient recursive watching compared with47implementations like `kqueue` available on most \*nix platforms. Chokidar still48does have to do some work to normalize the events received that way as well.49 50On most other platforms, the `fs.watch`-based implementation is the default, which51avoids polling and keeps CPU usage down. Be advised that chokidar will initiate52watchers recursively for everything within scope of the paths that have been53specified, so be judicious about not wasting system resources by watching much54more than needed.55 56## Getting started57 58Install with npm:59 60```sh61npm install chokidar62```63 64Then `require` and use it in your code:65 66```javascript67const chokidar = require('chokidar');68 69// One-liner for current directory70chokidar.watch('.').on('all', (event, path) => {71 console.log(event, path);72});73```74 75## API76 77```javascript78// Example of a more typical implementation structure79 80// Initialize watcher.81const watcher = chokidar.watch('file, dir, glob, or array', {82 ignored: /(^|[\/\\])\../, // ignore dotfiles83 persistent: true84});85 86// Something to use when events are received.87const log = console.log.bind(console);88// Add event listeners.89watcher90 .on('add', path => log(`File ${path} has been added`))91 .on('change', path => log(`File ${path} has been changed`))92 .on('unlink', path => log(`File ${path} has been removed`));93 94// More possible events.95watcher96 .on('addDir', path => log(`Directory ${path} has been added`))97 .on('unlinkDir', path => log(`Directory ${path} has been removed`))98 .on('error', error => log(`Watcher error: ${error}`))99 .on('ready', () => log('Initial scan complete. Ready for changes'))100 .on('raw', (event, path, details) => { // internal101 log('Raw event info:', event, path, details);102 });103 104// 'add', 'addDir' and 'change' events also receive stat() results as second105// argument when available: https://nodejs.org/api/fs.html#fs_class_fs_stats106watcher.on('change', (path, stats) => {107 if (stats) console.log(`File ${path} changed size to ${stats.size}`);108});109 110// Watch new files.111watcher.add('new-file');112watcher.add(['new-file-2', 'new-file-3', '**/other-file*']);113 114// Get list of actual paths being watched on the filesystem115var watchedPaths = watcher.getWatched();116 117// Un-watch some files.118await watcher.unwatch('new-file*');119 120// Stop watching.121// The method is async!122watcher.close().then(() => console.log('closed'));123 124// Full list of options. See below for descriptions.125// Do not use this example!126chokidar.watch('file', {127 persistent: true,128 129 ignored: '*.txt',130 ignoreInitial: false,131 followSymlinks: true,132 cwd: '.',133 disableGlobbing: false,134 135 usePolling: false,136 interval: 100,137 binaryInterval: 300,138 alwaysStat: false,139 depth: 99,140 awaitWriteFinish: {141 stabilityThreshold: 2000,142 pollInterval: 100143 },144 145 ignorePermissionErrors: false,146 atomic: true // or a custom 'atomicity delay', in milliseconds (default 100)147});148 149```150 151`chokidar.watch(paths, [options])`152 153* `paths` (string or array of strings). Paths to files, dirs to be watched154recursively, or glob patterns.155 - Note: globs must not contain windows separators (`\`),156 because that's how they work by the standard —157 you'll need to replace them with forward slashes (`/`).158 - Note 2: for additional glob documentation, check out low-level159 library: [picomatch](https://github.com/micromatch/picomatch).160* `options` (object) Options object as defined below:161 162#### Persistence163 164* `persistent` (default: `true`). Indicates whether the process165should continue to run as long as files are being watched. If set to166`false` when using `fsevents` to watch, no more events will be emitted167after `ready`, even if the process continues to run.168 169#### Path filtering170 171* `ignored` ([anymatch](https://github.com/es128/anymatch)-compatible definition)172Defines files/paths to be ignored. The whole relative or absolute path is173tested, not just filename. If a function with two arguments is provided, it174gets called twice per path - once with a single argument (the path), second175time with two arguments (the path and the176[`fs.Stats`](https://nodejs.org/api/fs.html#fs_class_fs_stats)177object of that path).178* `ignoreInitial` (default: `false`). If set to `false` then `add`/`addDir` events are also emitted for matching paths while179instantiating the watching as chokidar discovers these file paths (before the `ready` event).180* `followSymlinks` (default: `true`). When `false`, only the181symlinks themselves will be watched for changes instead of following182the link references and bubbling events through the link's path.183* `cwd` (no default). The base directory from which watch `paths` are to be184derived. Paths emitted with events will be relative to this.185* `disableGlobbing` (default: `false`). If set to `true` then the strings passed to `.watch()` and `.add()` are treated as186literal path names, even if they look like globs.187 188#### Performance189 190* `usePolling` (default: `false`).191Whether to use fs.watchFile (backed by polling), or fs.watch. If polling192leads to high CPU utilization, consider setting this to `false`. It is193typically necessary to **set this to `true` to successfully watch files over194a network**, and it may be necessary to successfully watch files in other195non-standard situations. Setting to `true` explicitly on MacOS overrides the196`useFsEvents` default. You may also set the CHOKIDAR_USEPOLLING env variable197to true (1) or false (0) in order to override this option.198* _Polling-specific settings_ (effective when `usePolling: true`)199 * `interval` (default: `100`). Interval of file system polling, in milliseconds. You may also200 set the CHOKIDAR_INTERVAL env variable to override this option.201 * `binaryInterval` (default: `300`). Interval of file system202 polling for binary files.203 ([see list of binary extensions](https://github.com/sindresorhus/binary-extensions/blob/master/binary-extensions.json))204* `useFsEvents` (default: `true` on MacOS). Whether to use the205`fsevents` watching interface if available. When set to `true` explicitly206and `fsevents` is available this supercedes the `usePolling` setting. When207set to `false` on MacOS, `usePolling: true` becomes the default.208* `alwaysStat` (default: `false`). If relying upon the209[`fs.Stats`](https://nodejs.org/api/fs.html#fs_class_fs_stats)210object that may get passed with `add`, `addDir`, and `change` events, set211this to `true` to ensure it is provided even in cases where it wasn't212already available from the underlying watch events.213* `depth` (default: `undefined`). If set, limits how many levels of214subdirectories will be traversed.215* `awaitWriteFinish` (default: `false`).216By default, the `add` event will fire when a file first appears on disk, before217the entire file has been written. Furthermore, in some cases some `change`218events will be emitted while the file is being written. In some cases,219especially when watching for large files there will be a need to wait for the220write operation to finish before responding to a file creation or modification.221Setting `awaitWriteFinish` to `true` (or a truthy value) will poll file size,222holding its `add` and `change` events until the size does not change for a223configurable amount of time. The appropriate duration setting is heavily224dependent on the OS and hardware. For accurate detection this parameter should225be relatively high, making file watching much less responsive.226Use with caution.227 * *`options.awaitWriteFinish` can be set to an object in order to adjust228 timing params:*229 * `awaitWriteFinish.stabilityThreshold` (default: 2000). Amount of time in230 milliseconds for a file size to remain constant before emitting its event.231 * `awaitWriteFinish.pollInterval` (default: 100). File size polling interval, in milliseconds.232 233#### Errors234 235* `ignorePermissionErrors` (default: `false`). Indicates whether to watch files236that don't have read permissions if possible. If watching fails due to `EPERM`237or `EACCES` with this set to `true`, the errors will be suppressed silently.238* `atomic` (default: `true` if `useFsEvents` and `usePolling` are `false`).239Automatically filters out artifacts that occur when using editors that use240"atomic writes" instead of writing directly to the source file. If a file is241re-added within 100 ms of being deleted, Chokidar emits a `change` event242rather than `unlink` then `add`. If the default of 100 ms does not work well243for you, you can override it by setting `atomic` to a custom value, in244milliseconds.245 246### Methods & Events247 248`chokidar.watch()` produces an instance of `FSWatcher`. Methods of `FSWatcher`:249 250* `.add(path / paths)`: Add files, directories, or glob patterns for tracking.251Takes an array of strings or just one string.252* `.on(event, callback)`: Listen for an FS event.253Available events: `add`, `addDir`, `change`, `unlink`, `unlinkDir`, `ready`,254`raw`, `error`.255Additionally `all` is available which gets emitted with the underlying event256name and path for every event other than `ready`, `raw`, and `error`. `raw` is internal, use it carefully.257* `.unwatch(path / paths)`: Stop watching files, directories, or glob patterns.258Takes an array of strings or just one string.259* `.close()`: **async** Removes all listeners from watched files. Asynchronous, returns Promise. Use with `await` to ensure bugs don't happen.260* `.getWatched()`: Returns an object representing all the paths on the file261system being watched by this `FSWatcher` instance. The object's keys are all the262directories (using absolute paths unless the `cwd` option was used), and the263values are arrays of the names of the items contained in each directory.264 265## CLI266 267If you need a CLI interface for your file watching, check out268[chokidar-cli](https://github.com/open-cli-tools/chokidar-cli), allowing you to269execute a command on each change, or get a stdio stream of change events.270 271## Install Troubleshooting272 273* `npm WARN optional dep failed, continuing fsevents@n.n.n`274 * This message is normal part of how `npm` handles optional dependencies and is275 not indicative of a problem. Even if accompanied by other related error messages,276 Chokidar should function properly.277 278* `TypeError: fsevents is not a constructor`279 * Update chokidar by doing `rm -rf node_modules package-lock.json yarn.lock && npm install`, or update your dependency that uses chokidar.280 281* Chokidar is producing `ENOSP` error on Linux, like this:282 * `bash: cannot set terminal process group (-1): Inappropriate ioctl for device bash: no job control in this shell`283 `Error: watch /home/ ENOSPC`284 * This means Chokidar ran out of file handles and you'll need to increase their count by executing the following command in Terminal:285 `echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p`286 287## Changelog288 289For more detailed changelog, see [`full_changelog.md`](.github/full_changelog.md).290- **v3.5 (Jan 6, 2021):** Support for ARM Macs with Apple Silicon. Fixes for deleted symlinks.291- **v3.4 (Apr 26, 2020):** Support for directory-based symlinks. Fixes for macos file replacement.292- **v3.3 (Nov 2, 2019):** `FSWatcher#close()` method became async. That fixes IO race conditions related to close method.293- **v3.2 (Oct 1, 2019):** Improve Linux RAM usage by 50%. Race condition fixes. Windows glob fixes. Improve stability by using tight range of dependency versions.294- **v3.1 (Sep 16, 2019):** dotfiles are no longer filtered out by default. Use `ignored` option if needed. Improve initial Linux scan time by 50%.295- **v3 (Apr 30, 2019):** massive CPU & RAM consumption improvements; reduces deps / package size by a factor of 17x and bumps Node.js requirement to v8.16 and higher.296- **v2 (Dec 29, 2017):** Globs are now posix-style-only; without windows support. Tons of bugfixes.297- **v1 (Apr 7, 2015):** Glob support, symlink support, tons of bugfixes. Node 0.8+ is supported298- **v0.1 (Apr 20, 2012):** Initial release, extracted from [Brunch](https://github.com/brunch/brunch/blob/9847a065aea300da99bd0753f90354cde9de1261/src/helpers.coffee#L66)299 300## Also301 302Why was chokidar named this way? What's the meaning behind it?303 304>Chowkidar is a transliteration of a Hindi word meaning 'watchman, gatekeeper', चौकीदार. This ultimately comes from Sanskrit _ चतुष्क_ (crossway, quadrangle, consisting-of-four). This word is also used in other languages like Urdu as (چوکیدار) which is widely used in Pakistan and India. 305 306## License307 308MIT (c) Paul Miller (<https://paulmillr.com>), see [LICENSE](LICENSE) file.309