text: const qs = require('querystring');
  const parseDuration = require('parse-duration');
  
  /**
   * @private
   */
  class Utils {
    static msToGoDurationStr(ms) {
      if (ms === undefined) {
        return undefined;
      }
  
      return ms + 'ms';
    }
  
    static goDurationStrToMs(str) {
      if (str === undefined) {
        return undefined;
      }
  
      return parseDuration(str);
    }
  
    static unpackArgs(first, args, first_index) {
      if (!first_index) {
        first_index = 0;
      }
      if (!Array.isArray(first)) {
        first = [first];
        for (var i = first_index + 1; i < args.length; ++i) {
          first.push(args[i]);
        }
      }
      return first;
    }
  
    static cbQsStringify(values) {
      var cbValues = {};
      for (var i in values) {
        if (values.hasOwnProperty(i)) {
          if (typeof values[i] === 'boolean') {
            cbValues[i] = values[i] ? 1 : 0;
          } else {
            cbValues[i] = values[i];
          }
        }
      }
      return qs.stringify(cbValues);
    }
  }
  
  module.exports = Utils;
  