gistfile1.js

Sync.prototype.sync = function(fn) {
  var self = this,
      batch = new Batch,
      tag = this.tag;

  Note.all(function(err, notes) {
    notes = notes.select(function(note) { return ~note.tags.indexOf(tag); })
    if(!notes.length) return fn();

    notes.each(function(note) {
      var action = (note.deleted) ? 'remove' : 'update';
      batch.push(function(done) { self[action](note, done); });
    });
  });

  batch.end(fn);
};