toBlock() {
    var str = '{'
      , key
      , val;

    for (key in this.vals) {
      val = this.get(key);
      if ('object' == val.first.nodeName) {
        str += key + ' ' + val.first.toBlock();
      } else {
        switch (key) {
          case '@charset':
            str += key + ' ' + val.first.toString() + ';';
            break;
          default:
            str += key + ':' + toString(val) + ';';
        }
      }
    }

    str += '}';

    return str;

    function toString(node) {
      if (node.nodes) {
        return node.nodes.map(toString).join(node.isList ? ',' : ' ');
      } else if ('literal' == node.nodeName && ',' == node.val) {
        return '\\,';
      }
      return node.toString();
    }
  }
Convert object to string with properties.

@return {String}
@api private