code: function parseCode2ChartOption(optionCode) {
    const reservedKeys = ['type', 'url'];
    let options = {};
    if (util.isUndefined(optionCode)) {
      return options;
    }
  
    const optionLines = optionCode.split(REGEX_LINE_ENDING);
    optionLines.forEach(line => {
      let [keyString, ...values] = line.split(OPTION_DELIMITER);
      let value = values.join(OPTION_DELIMITER);
      keyString = keyString.trim();
      if (value.length === 0) {
        return;
      }
  
      try {
        value = JSON.parse(value.trim());
      } catch (e) {
        value = value.trim();
      }
  
      // parse keys
      let [...keys] = keyString.split('.');
      let topKey = keys[0];
      if (util.inArray(topKey, reservedKeys) >= 0) {
        // reserved keys for chart plugin option
        keys.unshift('editorChart');
      } else if (keys.length === 1) {
        // short names for `chart`
        keys.unshift('chart');
      } else if (topKey === 'x' || topKey === 'y') {
        // short-handed keys
        keys[0] = `${topKey}Axis`;
      }
  
      let option = options;
      for (let i = 0; i < keys.length; i += 1) {
        let key = keys[i];
        option[key] = option[key] || (keys.length - 1 === i ? value : {});
        option = option[key];
      }
    });
  
    return options;
  }
docs: parse option code
  @param {string} optionCode - option code
  @returns {Object} - tui.chart option string
  @see https://nhn.github.io/tui.chart/latest/tui.chart.html
  @ignore