function convertWithRegeneratorPluginOnly(inputFile, outputFile, callback) {
  var transformOptions = {
    plugins:[require("regenerator-transform")],
    parserOpts: {
      sourceType: "module",
      allowImportExportEverywhere: true,
      allowReturnOutsideFunction: true,
      allowSuperOutsideMethod: true,
      strictMode: false,
      plugins: ["*", "jsx", "flow"]
    },
    ast: true
  };

  fs.readFile(inputFile, "utf-8", function(err, input) {
    if (err) {
      return callback(err);
    }

    var { code: output, ast } = babel.transformSync(input, transformOptions);
    fs.writeFileSync(outputFile, output);
    try {
      checkDuplicatedNodes(babel, ast);
    } catch (err) {
      err.message = "Occurred while transforming: " + inputFile + "\n" + err.message;
      throw err;
    }
    callback();
  });
}
Comvert without using the preset (which also transforms things like classes and arrows)