A globbing fs.watch wrapper built from the best parts of other fine watch libs.
Compatible with Node.js >= 4.x, Windows, macOS, and Linux.

Install the module with: npm install gaze or place into your package.json and run npm install.

const gaze = require('gaze');

// Watch all .js files/dirs in process.cwd()
gaze('**/*.js', (err, watcher) => {
  // Files have all started watching

  // Get all watched files
  const watched = watcher.watched();

  // On file changed
  watcher.on('changed', filepath => {
    console.log(filepath + ' was changed');
  });

  // On file added
  watcher.on('added', filepath => {
    console.log(filepath + ' was added');
  });

  // On file deleted
  watcher.on('deleted', filepath => {
    console.log(filepath + ' was deleted');
  });

  // On changed/added/deleted
  watcher.on('all', (event, filepath) => {
    console.log(filepath + ' was ' + event);
  });

  // Get watched files with relative paths
  const files = watcher.relative();
});

// Also accepts an array of patterns
gaze(['stylesheets/*.css', 'images/**/*.png'], () => {
  // Add more patterns later to be watched
  watcher.add(['js/*.js']);
});

const {Gaze} = require('gaze');

const gaze = new Gaze('**/*');

// Files have all started watching
gaze.on('ready', watcher => { });

// A file has been added/changed/deleted has occurred
gaze.on('all', (event, filepath) => { });

gaze('**/*', (error, watcher) => {
  if (error) {
    // Handle error if it occurred while starting up
  }
});

// Or with the alternative interface
const gaze = new Gaze();
gaze.on('error', error => {
  // Handle error here
});
gaze.add('**/*');

See isaacs's minimatch for more information on glob patterns.

• patterns {String|Array} File patterns to be matched
• options {Object}
• callback {Function}
  • err {Error | null}
  • watcher {Object} Instance of the Gaze watcher

Create a Gaze object by instancing the gaze.Gaze class.

const Gaze = require('gaze').Gaze;
const gaze = new Gaze(pattern, options, callback);

• options The options object passed in.
  • interval {integer} Interval to pass to fs.watchFile
  • debounceDelay {integer} Delay for events called in succession for the same file/event in milliseconds
  • mode {string} Force the watch mode. Either 'auto' (default), 'watch' (force native events), or 'poll' (force stat polling).
  • cwd {string} The current working directory to base file patterns from. Default is process.cwd().

• ready(watcher) When files have been globbed and watching has begun.
• all(event, filepath) When an added, changed, renamed, or deleted event occurs.
• added(filepath) When a file has been added to a watch directory.
• changed(filepath) When a file has been changed.
• deleted(filepath) When a file has been deleted.
• renamed(newPath, oldPath) When a file has been renamed.
• end() When the watcher is closed and watches have been removed.
• error(err) When an error occurs.
• nomatch When no files have been matched.

• emit(event, [...]) Wrapper for EventEmitter.emit. added|changed|renamed|deleted events will also trigger the all event.
• close() Unwatch all files and reset the watch instance.
• add(patterns, callback) Adds file(s) patterns to be watched.
• remove(filepath) Removes a file or directory from being watched. Does not recurse directories.
• watched() Returns the currently watched files.
• relative([dir, unixify]) Returns the currently watched files with relative paths.
  • dir {string} Only return relative files for this directory.
  • unixify {boolean} Return paths with / instead of \\ if on Windows.

Other great watch libraries to try are:

• paulmillr's chokidar
• amasad's sane
• mikeal's watch
• github's pathwatcher
• bevry's watchr

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using grunt.

• 1.1.3 - Fix for Node 10 support (@aredridel). Officially dropping support for Node < 4.
• 1.1.2 - Prevent more ENOENT errors from escaping (@alexgorbatchev).
• 1.1.1 - Prevent fs.watch errors from escaping error handler (@rosen-vladimirov). Fix _addToWatched without path.sep (@wyicwx).
• 1.1.0 - Update to [email protected] with minimatch >= 3.0.0.
• 1.0.0 - Revert back to 0.5.2. Drop support for Node.js v0.8. Fix for maxListeners. Update globule to 0.2.0.
• 0.6.4 - Catch and emit error from readdir (@oconnore). Fix for 0 maxListeners. Use graceful-fs to avoid EMFILE errors in other places fs is used. Better method to determine if pathwatcher was built. Fix keeping process alive too much, only init pathwatcher if a file is being watched. Set min required to Windows Vista when building on Windows (@pvolok).
• 0.6.3 - Add support for Node.js v0.11
• 0.6.2 - Fix argument error with watched(). Fix for erroneous added events on folders. Ignore msvs build error 4244.
• 0.6.1 - Fix for absolute paths.
• 0.6.0 - Uses native OS events (fork of pathwatcher) but can fall back to stat polling. Everything is async to avoid blocking, including relative() and watched(). Better error handling. Update to [email protected]. No longer watches cwd by default. Added mode option. Better EMFILE message. Avoids ENOENT errors with symlinks. All constructor arguments are optional.
• 0.5.2 - Fix for ENOENT error with non-existent symlinks [BACKPORTED].
• 0.5.1 - Use setImmediate (process.nextTick for Node.js v0.8) to defer ready/nomatch events (@amasad).
• 0.5.0 - Process is now kept alive while watching files. Emits a nomatch event when no files are matching.
• 0.4.3 - Track file additions in newly created folders (@brett-shwom).
• 0.4.2 - Fix .remove() method to remove a single file in a directory (@kaelzhang). Fixing “Cannot call method 'call' of undefined” (@krasimir). Track new file additions within folders (@brett-shwom).
• 0.4.1 - Fix watchDir not respecting close in race condition (@chrisirhc).
• 0.4.0 - Drop support for Node.js v0.6. Use globule for file matching. Avoid Node.js v0.10 path.resolve/join errors. Register new files when added to non-existent folder. Multiple instances can now poll the same files (@jpommerening).
• 0.3.4 - Code clean up. Fix “path must be strings” errors (@groner). Fix incorrect added events (@groner).
• 0.3.3 - Fix for multiple patterns with negate.
• 0.3.2 - Emit end before removeAllListeners.
• 0.3.1 - Fix added events within subfolder patterns.
• 0.3.0 - Handle safewrite events, forceWatchMethod option removed, bug fixes and watch optimizations (@rgaskill).
• 0.2.2 - Fix issue where subsequent add calls dont get watched (@samcday). removeAllListeners on close.
• 0.2.1 - Fix issue with invalid added events in current working dir.
• 0.2.0 - Support and mark folders with path.sep. Add forceWatchMethod option. Support renamed events.
• 0.1.6 - Recognize the cwd option properly
• 0.1.5 - Catch “too many open file” errors
• 0.1.4 - Really fix the race condition with 2 watches
• 0.1.3 - Fix race condition with 2 watches
• 0.1.2 - Read triggering changed event fix
• 0.1.1 - Minor fixes
• 0.1.0 - Initial release

Copyright (c) 2018 Kyle Robinson Young
Licensed under the MIT license.