Function isInstalled

bin/webpack-dev-server.js:43–54

(packageName)

 * @returns {boolean} is the package installed?
 */
const isInstalled = (packageName) => {
  if (process.versions.pnp) {
    return true;
  }

  try {
    require.resolve(packageName);
    return true;
  } catch {
    return false;
  }
};

/**
 * @param {CliOption} cli options