opts() {
    if (this._storeOptionsAsProperties) {
      // Preserve original behaviour so backwards compatible when still using properties
      const result = {};
      const len = this.options.length;

      for (let i = 0; i < len; i++) {
        const key = this.options[i].attributeName();
        result[key] =
          key === this._versionOptionName ? this._version : this[key];
      }
      return result;
    }

    return this._optionValues;
  }
Return an object containing local option values as key-value pairs.

@return {object}