touch-and-go

var Watcher = require('touch-and-go').Watcher;
var watcher = new Watcher('/path/to/somewhere',function(o){return /\.txt$/.test(o)});
// or
// var w = require('touch-and-go').watcher;
// var watcher = w('/path/to/somewhere',function(o){return /\.txt$/.test(o)});
 
// added or changed
watcher.on('changed',function(filepath){
  console.log('abs path: '+filepath);
});
 
// removed
watcher.on('removed',function(filepath){
  // do something
});
 
// start observing
watcher.start();
 
// stop observing
watcher.stop();