How to use the mkdirp.promise function in mkdirp

runAsync: _asyncToGenerator(function* (env) {
    var argv = env.argv;
    var args = argv._;

    // Here is what this will do

    // 0. If there is a command line argument, make a new directory in the current directory and chdir to it
    var dirName = args[1];
    var originalCwd = process.cwd();
    if (dirName) {
      dirName = dirName.toString();
      yield mkdirp.promise(dirName);
      log('Setting up an Exponent project at', path.resolve(dirName));
      process.chdir(dirName);
    }

    // 1. If there is no package.json in the current directory, run npm init
    var pkgJsonFile = jsonFile('package.json');
    var pkg;
    try {
      pkg = yield pkgJsonFile.readAsync();
    } catch (e) {
      //console.error(e);

      // No package.json, so let's create it
      log(crayon.cyan('No package.json file found. Using `npm init` to help you create one.'));
      log(crayon.cyan('Answer the questions and a package.json will be created for you.'));
      var _zero = yield spawnAsync('npm', ['init'], { stdio: 'inherit' });

description: "Hello Exponent!",
    author,
    //license: "MIT",
    // scripts: {
    //   "test": "echo \"Error: no test specified\" && exit 1"
    // },
  }, info);

  let pkgJson = jsonFile(path.join(root, 'package.json'));

  let exists = await existsAsync(pkgJson.file);
  if (exists && !opts.force) {
    throw NewExpError('WONT_OVERWRITE_WITHOUT_FORCE', "Refusing to create new Exp because package.json already exists at root");
  }

  await mkdirp.promise(root);

  let result = await pkgJson.writeAsync(data);

  // Copy the template directory, which contains node_modules, without its
  // package.json
  await fsExtra.promise.copy(TEMPLATE_ROOT, root, {
    filter: filePath => filePath !== path.join(TEMPLATE_ROOT, 'package.json')
  });

  // Custom code for replacing __NAME__ in main.js
  let mainJs = await fs.readFile.promise(path.join(TEMPLATE_ROOT, 'main.js'), 'utf8');
  let customMainJs = mainJs.replace(/__NAME__/g, data.name);
  result = await fs.writeFile.promise(path.join(root, 'main.js'), customMainJs, 'utf8');

  return data;
}

author: author,
    dependencies: dependencies
  }, //license: "MIT",
  // scripts: {
  //   "test": "echo \"Error: no test specified\" && exit 1"
  // },
  info);

  var pkgJson = jsonFile(path.join(root, 'package.json'));

  var exists = yield existsAsync(pkgJson.file);
  if (exists && !opts.force) {
    throw NewExpError('WONT_OVERWRITE_WITHOUT_FORCE', "Refusing to create new Exp because package.json already exists at root");
  }

  yield mkdirp.promise(root);

  var result = yield pkgJson.writeAsync(data);

  yield fsExtra.promise.copy(TEMPLATE_ROOT, root);

  // Custom code for replacing __NAME__ in main.js
  var mainJs = yield fs.readFile.promise(path.join(TEMPLATE_ROOT, 'main.js'), 'utf8');
  var customMainJs = mainJs.replace(/__NAME__/g, data.name);
  result = yield fs.writeFile.promise(path.join(root, 'main.js'), customMainJs, 'utf8');

  // Intall react-native
  yield _installReactNativeInNewProjectWithRoot(root);

  return data;
});

var _installReactNativeInNewProjectWithRoot = _asyncToGenerator(function* (root) {
  var nodeModulesPath = path.join(root, 'node_modules');
  yield mkdirp.promise(nodeModulesPath);
  yield fsExtra.copy.promise(path.join(__dirname, '../../node_modules/react-native'), path.join(nodeModulesPath, 'react-native'));
});