vercel__flags/apps/playground/utils.ts

import { randomBytes } from 'crypto';
import { dedupe } from 'flags/next';
import { cookies, headers } from 'next/headers';
import type { Entity } from './types';

export const identify = dedupe(async (): Promise<Entity> => {
  const cookieStore = await cookies();
  const headerStore = await headers();
  const visitorId =
    cookieStore.get('visitorId')?.value ??
    headerStore.get('x-visitor-id') ??
    generateRandomId();

  return {
    visitor: {
      id: visitorId,
    },
  };
});

export function generateRandomId(length = 16) {
  return randomBytes(length)
    .toString('base64') // Convert to base64
    .replace(/\+/g, '0') // Replace '+' with '0' to make it alphanumeric
    .replace(/\//g, '1') // Replace '/' with '1'
    .substring(0, length); // Trim to the desired length
}