rallly/apps/landing/src/utils/absolute-url.ts

const port = process.env.PORT || 3000;

const getVercelUrl = () => {
  return process.env.NEXT_PUBLIC_VERCEL_URL
    ? `https://${process.env.NEXT_PUBLIC_VERCEL_URL}`
    : null;
};

function joinPath(baseUrl: string, subpath = "") {
  if (subpath) {
    const url = new URL(subpath, baseUrl);
    return url.href;
  }

  return baseUrl;
}

export function absoluteUrl(subpath = "", query?: Record<string, string>) {
  const queryString = query
    ? `?${Object.entries(query)
        .map(([key, value]) => `${key}=${encodeURIComponent(value)}`)
        .join("&")}`
    : "";
  const baseUrl =
    process.env.NEXT_PUBLIC_BASE_URL ??
    getVercelUrl() ??
    `http://localhost:${port}`;

  return joinPath(baseUrl, subpath) + queryString;
}