Function validateEntrypoint

packages/next/src/utils.ts:121–132

* Validate if the entrypoint is allowed to be used

(entrypoint: string)

 * Validate if the entrypoint is allowed to be used
 */
function validateEntrypoint(entrypoint: string) {
  if (
    !/package\.json$/.exec(entrypoint) &&
    !/next\.config\.js$/.exec(entrypoint)
  ) {
    throw new NowBuildError({
      message:
        'Specified "src" for "@vercel/next" has to be "package.json" or "next.config.js"',
      code: 'NEXT_INCORRECT_SRC',
    });
  }
}

/**
 * Exclude certain files from the files object