Function normalizeQueryParam

pages/api/auth/callback.ts:20–26

* Normalize query param that could be string | string[] | undefined to a single string

(
  param: string | string[] | undefined,
)

 * Normalize query param that could be string | string[] | undefined to a single string
 */
function normalizeQueryParam(
  param: string | string[] | undefined,
): string | undefined {
  if (param === undefined) return undefined;
  if (Array.isArray(param)) return param[0];
  return param;
}

export default async function handler(
  req: NextApiRequest,