selectize_filter.js

    Selectize.define('filter', function(options) {
      var self = this;

      options.filter = options.filter || function(results) {
        return results;
      };

      this.search = (function() {
        var original = self.search;
        return function(query) {
          var results = original.bind(self)(query);
          results.items = options.filter.bind(self)(results.items);
          results.total = results.items.length;
          return results;
        };
      })();
    });


    $('#the-select').selectize({
      plugins: {
        filter: function(items) {
          var ponies_only = $('#checkbox').is(':checked');
          return items.filter(function(item) {
            return !ponies_only || item.data.indefOf('pony') !== -1;
          });
        }
      }
    })