code: function toPathString(value) {
      if (value === undefined || value == null) {
          return '';
      }
      else if (value instanceof Date) {
          return value.toISOString();
      }
      else if (Array.isArray(value)) {
          // Array of arrays have inner elements joined by a pipe
          if (value.length > 0 && Array.isArray(value[0])) {
              let pipedArray = [];
              for (let c of value) {
                  pipedArray.push(c.join('|'));
              }
              return pipedArray.join(',');
          }
          else {
              // Simple array goes to a CSV
              return value.join(',');
          }
      }
      else {
          return value.toString();
      }
  }
docs: Note that this does not call encodeURIComponent, since this string may be included in a url (which needs it), or passed to superagent, which takes care of the encoding.