How to use the @expo/config.isUsingYarn function in @expo/config

).ejectMethod;

  if (ejectMethod === 'bare') {
    await ejectToBareAsync(projectRoot);
    log.nested(chalk.green('Ejected successfully!'));
    log.newLine();
    log.nested(
      `Before running your app on iOS, make sure you have CocoaPods installed and initialize the project:`
    );
    log.nested('');
    log.nested(`  cd ios`);
    log.nested(`  pod install`);
    log.nested('');
    log.nested('Then you can run the project:');
    log.nested('');
    let packageManager = ConfigUtils.isUsingYarn(projectRoot) ? 'yarn' : 'npm';
    log.nested(`  ${packageManager === 'npm' ? 'npm run android' : 'yarn android'}`);
    log.nested(`  ${packageManager === 'npm' ? 'npm run ios' : 'yarn ios'}`);
    await warnIfDependenciesRequireAdditionalSetupAsync(projectRoot);
  } else if (ejectMethod === 'expokit') {
    await loginOrRegisterIfLoggedOut();
    await Detach.detachAsync(projectRoot, options);
    log(chalk.green('Ejected successfully!'));
  } else if (ejectMethod === 'cancel') {
    // we don't want to print the survey for cancellations
    log('OK! If you change your mind you can run this command again.');
  } else {
    throw new Error(
      `Unrecognized eject method "${ejectMethod}". Valid options are: bare, expokit.`
    );
  }
}

export function createForProject(projectRoot: string, options: CreateForProjectOptions = {}) {
  console.warn(
    '`createForProject` is deprecated in favor of `createForProject` from `@expo/package-manager`'
  );
  let PackageManager;
  if (options.npm) {
    PackageManager = NpmPackageManager;
  } else if (options.yarn) {
    PackageManager = YarnPackageManager;
  } else if (isUsingYarn(projectRoot)) {
    PackageManager = YarnPackageManager;
  } else {
    PackageManager = NpmPackageManager;
  }
  return new PackageManager({ cwd: projectRoot });
}

async function ejectToBareAsync(projectRoot: string): Promise {
  const useYarn = ConfigUtils.isUsingYarn(projectRoot);
  const npmOrYarn = useYarn ? 'yarn' : 'npm';
  const { configPath, configName } = ConfigUtils.findConfigFile(projectRoot);
  const { exp, pkg } = await ConfigUtils.readConfigJsonAsync(projectRoot);

  const configBuffer = await fse.readFile(configPath);
  const appJson = configName === 'app.json' ? JSON.parse(configBuffer.toString()) : {};

  /**
   * Perform validations
   */
  if (!exp.sdkVersion) throw new Error(`Couldn't read ${configName}`);

  if (!Versions.gteSdkVersion(exp, '34.0.0')) {
    throw new Error(`Ejecting to a bare project is only available for SDK 34 and higher`);
  }

const port = await getAvailablePortAsync({
    defaultPort: options.port,
  });
  webpackServerPort = port;

  ProjectUtils.logInfo(
    projectRoot,
    WEBPACK_LOG_TAG,
    withTag(
      `Starting ${serverName} on port ${webpackServerPort} in ${chalk.underline(env.mode)} mode.`
    )
  );

  const protocol = env.https ? 'https' : 'http';
  const urls = prepareUrls(protocol, '::', webpackServerPort);
  const useYarn = ConfigUtils.isUsingYarn(projectRoot);
  const appName = await getProjectNameAsync(projectRoot);
  const nonInteractive = validateBoolOption(
    'nonInteractive',
    options.nonInteractive,
    !process.stdout.isTTY
  );

  let server: DevServer;

  devServerInfo = {
    urls,
    protocol,
    useYarn,
    appName,
    nonInteractive,
    port: webpackServerPort!,