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glob-watcher

Watch globs and execute a function upon change, with intelligent defaults for debouncing and queueing.

glob-watcher

Watch globs and execute a function upon change, with intelligent defaults for debouncing and queueing.

var watch = require('glob-watcher');
 
watch(['./*.js', '!./something.js'], function(done){
  // This function will be called each time a globbed file is changed 
  // but is debounced with a 200ms delay (default) and queues subsequent calls 
 
  // Make sure to signal async completion with the callback 
  // or by returning a stream, promise, observable or child process 
  done();
 
  // if you need access to the `path` or `stat` object, listen 
  // for the `change` event (see below) 
 
  // if you need to listen to specific events, use the returned 
  // watcher instance (see below) 
});
 
// Raw chokidar instance 
var watcher = watch(['./*.js', '!./something.js']);
 
// Listen for the 'change' event to get `path`/`stat` 
// No async completion available because this is the raw chokidar instance 
watcher.on('change', function(pathstat) {
  // `path` is the path of the changed file 
  // `stat` is an `fs.Stat` object (not always available) 
});
 
// Listen for other events 
// No async completion available because this is the raw chokidar instance 
watcher.on('add', function(pathstat) {
  // `path` is the path of the changed file 
  // `stat` is an `fs.Stat` object (not always available) 
});

Takes a path string, an array of path strings, a [glob][node-glob] string or an array of [glob][node-glob] strings as globs to watch on the filesystem. Also optionally takes options to configure the watcher and a fn to execute when a file changes.

Returns an instance of chokidar.

If the fn is passed, it will be called when the watcher emits a change, add or unlink event. It is automatically debounced with a default delay of 200 milliseconds and subsequent calls will be queued and called upon completion. These defaults can be changed using the options.

The fn is passed a single argument, callback, which is a function that must be called when work in the fn is complete. Instead of calling the callback function, async completion can be signalled by:

  • Returning a Stream or EventEmitter
  • Returning a Child Process
  • Returning a Promise
  • Returning an Observable

Once async completion is signalled, if another run is queued, it will be executed.

If set to false the fn is called during chokidar instantiation as it discovers the file paths. Useful if it is desirable to trigger the fn during startup.

Passed through to chokidar, but defaulted to true instead of false.

Type: Boolean

Default: true

The delay to wait before triggering the fn. Useful for waiting on many changes before doing the work on changed files, e.g. find-and-replace on many files.

Type: Number

Default: 200 (milliseconds)

Whether or not a file change should queue the fn execution if the fn is already running. Useful for a long running fn.

Type: Boolean

Default: true

Options are passed directly to lodash.debounce and chokidar, so all their options are supported. Any debounce-related options are documented in lodash.debounce. Any chokidar-related options are documented in chokidar.

MIT