code: function Reader(data, ctors) {
          if (!_.isObject(data)) {
              console.error("Reader constructor: 'data' parameter should be JSON object");
              return;
          }
          this.data = data;
          this.ctors = ctors;
          this.current = this.data;
          this.idMap = {};
      }
docs: Reader Class
  @constructor
  @param {Object} data
  @param {Object.<string, constructor>} ctors