function getAdditionalModulePaths()

in config/modules.js [14:48]

• 20 lines of code
• 5 McCabe index (conditional complexity)

function getAdditionalModulePaths(options = {}) {
  const baseUrl = options.baseUrl;

  // We need to explicitly check for null and undefined (and not a falsy value) because
  // TypeScript treats an empty string as `.`.
  if (baseUrl == null) {
    // If there's no baseUrl set we respect NODE_PATH
    // Note that NODE_PATH is deprecated and will be removed
    // in the next major release of create-react-app.

    const nodePath = process.env.NODE_PATH || '';
    return nodePath.split(path.delimiter).filter(Boolean);
  }

  const baseUrlResolved = path.resolve(paths.appPath, baseUrl);

  // We don't need to do anything if `baseUrl` is set to `node_modules`. This is
  // the default behavior.
  if (path.relative(paths.appNodeModules, baseUrlResolved) === '') {
    return null;
  }

  // Allow the user set the `baseUrl` to `appSrc`.
  if (path.relative(paths.appSrc, baseUrlResolved) === '') {
    return [paths.appSrc];
  }

  // Otherwise, throw an error.
  throw new Error(
    chalk.red.bold(
      "Your project's `baseUrl` can only be set to `src` or `node_modules`." +
        ' Create React App does not support other values at this time.'
    )
  );
}