1.js

var fs = require('fs');

var filename = './1.txt';

function test() {
  process.stdout.write('.');
  fs.writeFileSync(filename, 'almost empty');
  var watch = fs.watch(filename, function(event, filename) {
    watch.close();
    test();
  });
  setTimeout(function() {
    fs.unlinkSync(filename);
  }, 100);
}

test();