Function normalizeHostname

browse/src/url-validation.ts:48–56

* Normalize hostname for blocklist comparison: * - Strip trailing dot (DNS fully-qualified notation) * - Strip IPv6 brackets (URL.hostname includes [] for IPv6) * - Resolve hex (0xA9FEA9FE) and decimal (2852039166) IP representations

(hostname: string)

 * - Resolve hex (0xA9FEA9FE) and decimal (2852039166) IP representations
 */
function normalizeHostname(hostname: string): string {
  // Strip IPv6 brackets
  let h = hostname.startsWith('[') && hostname.endsWith(']')
    ? hostname.slice(1, -1)
    : hostname;
  // Strip trailing dot
  if (h.endsWith('.')) h = h.slice(0, -1);
  return h;
}

/**
 * Check if a hostname resolves to the link-local metadata IP 169.254.169.254.