code: function (input, prefix) {
      _.forOwn(input, function (value, key) {
        if ((/[^\w-]/).test(key)) {
          console.warn(key + ': the key format is not valid');
        }
        if (_.isPlainObject(value)) {
          return recursion(value, prefix ? [prefix, key].join('_') : key);
        }
        result[(prefix ? [null, prefix, key] : [null, key]).join('_')] =
          _.isFinite(value) ? value : _.truncate(_.toString(value), {length: 32765}); // 32765 + 1
      });
    }
docs: recursion function for key-value aggregation 32766 bytes is the maximum length for a field