code: function resolveParserOptions(parserName, providedOptions, enabledEnvironments) {
      const parserOptionsFromEnv = enabledEnvironments
          .filter(env => env.parserOptions)
          .reduce((parserOptions, env) => ConfigOps.merge(parserOptions, env.parserOptions), {});
  
      const mergedParserOptions = ConfigOps.merge(parserOptionsFromEnv, providedOptions || {});
  
      const isModule = mergedParserOptions.sourceType === "module";
  
      if (isModule) {
  
          // can't have global return inside of modules
          mergedParserOptions.ecmaFeatures = Object.assign({}, mergedParserOptions.ecmaFeatures, { globalReturn: false });
      }
  
      mergedParserOptions.ecmaVersion = normalizeEcmaVersion(mergedParserOptions.ecmaVersion, isModule);
  
      return mergedParserOptions;
  }
docs: Combines the provided parserOptions with the options from environments
  @param {string} parserName The parser name which uses this options.
  @param {Object} providedOptions The provided 'parserOptions' key in a config
  @param {Environment[]} enabledEnvironments The environments enabled in configuration and with inline comments
  @returns {Object} Resulting parser options after merge