/**
 * Given a URL as a string and a base URL it will make the URL relative
 * if the parsed protocol and host is the same as the one in the base
 * URL. Otherwise it returns the same URL string.
 */
export function relativizeURL(url: string | string, base: string | URL) {
  const baseURL = typeof base === 'string' ? new URL(base) : base
  const relative = new URL(url, base)
  const origin = `${baseURL.protocol}//${baseURL.host}`
  return `${relative.protocol}//${relative.host}` === origin
    ? relative.toString().replace(origin, '')
    : relative.toString()
}