HTML form to JavaScript object

(function($) {
  return $.fn.serializeObject = function() {
    var json, patterns, push_counters,
      _this = this;
    json = {};
    push_counters = {};
    patterns = {
      validate: /^[a-zA-Z][a-zA-Z0-9_]*(?:\[(?:\d*|[a-zA-Z0-9_]+)\])*$/,
      key: /[a-zA-Z0-9_]+|(?=\[\])/g,
      push: /^$/,
      fixed: /^\d+$/,
      named: /^[a-zA-Z0-9_]+$/
    };
    this.build = function(base, key, value) {
      base[key] = value;
      return base;
    };
    this.push_counter = function(key) {
      if (push_counters[key] === void 0) {
        push_counters[key] = 0;
      }
      return push_counters[key]++;
    };
    $.each($(this).serializeArray(), function(i, elem) {
      var k, keys, merge, re, reverse_key;
      if (!patterns.validate.test(elem.name)) {
        return;
      }
      keys = elem.name.match(patterns.key);
      merge = elem.value;
      reverse_key = elem.name;
      while ((k = keys.pop()) !== void 0) {
        if (patterns.push.test(k)) {
          re = new RegExp("\\[" + k + "\\]$");
          reverse_key = reverse_key.replace(re, '');
          merge = _this.build([], _this.push_counter(reverse_key), merge);
        } else if (patterns.fixed.test(k)) {
          merge = _this.build([], k, merge);
        } else if (patterns.named.test(k)) {
          merge = _this.build({}, k, merge);
        }
      }
      return json = $.extend(true, json, merge);
    });
    return json;
  };
})(jQuery);