Function createApp

src/install.js:20–95

(name, verbose, useNpm, inplace, addons, alias, installDependencies)

const { loadFiles } = require('./loaders');

async function createApp(name, verbose, useNpm, inplace, addons, alias, installDependencies) {
  const root = path.resolve(name);
  const appName = path.basename(root);

  fs.ensureDirSync(name);

  console.log(`Creating a new React app in ${chalk.green(root)}.`);
  console.log();

  const useYarn = useNpm ? false : shouldUseYarn();
  const command = useYarn ? 'yarn' : 'npm run';

  const { packageJson, dependencies, devDependencies } = await resolvePackage({
    addons,
    appName,
    command,
  });

  fs.writeFileSync(path.join(root, 'package.json'), JSON.stringify(packageJson, null, 2) + os.EOL);

  const originalDirectory = process.cwd();
  process.chdir(root);
  if (!useYarn && !checkThatNpmCanReadCwd()) {
    process.exit(1);
  }

  if (!semver.satisfies(process.version, '>=6.0.0')) {
    console.log(
      chalk.yellow(
        `You are using Node ${process.version} so the project will be bootstrapped with an old unsupported version of tools.\n\n` +
          `Please update to Node 6 or higher for a better, fully supported experience.\n`
      )
    );
  }

  if (!useYarn) {
    const npmInfo = checkNpmVersion();
    if (!npmInfo.hasMinNpm) {
      if (npmInfo.npmVersion) {
        console.log(
          chalk.yellow(
            `You are using npm ${npmInfo.npmVersion} so the project will be bootstrapped with an old unsupported version of tools.\n\n` +
              `Please update to npm 3 or higher for a better, fully supported experience.\n`
          )
        );
      }
    }
  }

  if (useYarn) {
    let yarnUsesDefaultRegistry = true;
    try {
      yarnUsesDefaultRegistry =
        execSync('yarnpkg config get registry').toString().trim() ===
        'https://registry.yarnpkg.com';
    } catch (e) {
      // ignore
    }