onHandleCodeParser(parser, parserOption, filePath, code) {
    const ev = new PluginEvent();
    ev.data = {parser, parserOption, filePath, code};
    this._execHandler('onHandleCodeParser', ev);
    return {parser: ev.data.parser, parserOption: ev.data.parserOption};
  }
handle code parser.
@param {function(code: string)} parser - original js parser.
@param {object} parserOption - default babylon options.
@param {string} filePath - source code file path.
@param {string} code - original code.
@returns {{parser: function(code: string), parserOption: Object}} handled parser.