url: fix url.format with ipv6 hostname

Fixes: #36654
PR-URL: #36665
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Yash Ladha <yash@yashladha.in>

Author: Lxxyx

lib/url.js

@@ -26,6 +26,7 @@ const {
  ObjectCreate,
  ObjectKeys,
  SafeSet,
+ StringPrototypeCharCodeAt,
 }=primordials;
 
 const{ toASCII }=require('internal/idna');
@@ -156,6 +157,14 @@ function urlParse(url, parseQueryString, slashesDenoteHost) {
 returnurlObject;
 }
 
+functionisIpv6Hostname(hostname){
+return(
+StringPrototypeCharCodeAt(hostname,0)===CHAR_LEFT_SQUARE_BRACKET&&
+StringPrototypeCharCodeAt(hostname,hostname.length-1)===
+CHAR_RIGHT_SQUARE_BRACKET
+);
+}
+
 Url.prototype.parse=functionparse(url,parseQueryString,slashesDenoteHost){
 validateString(url,'url');
 
@@ -364,8 +373,7 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
 
 // If hostname begins with [ and ends with ]
 // assume that it's an IPv6 address.
-constipv6Hostname=hostname.charCodeAt(0)===CHAR_LEFT_SQUARE_BRACKET&&
-hostname.charCodeAt(hostname.length-1)===CHAR_RIGHT_SQUARE_BRACKET;
+constipv6Hostname=isIpv6Hostname(hostname);
 
 // validate a little.
 if(!ipv6Hostname){
@@ -590,7 +598,7 @@ Url.prototype.format = function format() {
 host=auth+this.host;
 }elseif(this.hostname){
 host=auth+(
-this.hostname.includes(':') ?
+this.hostname.includes(':')&&!isIpv6Hostname(this.hostname)?
 '['+this.hostname+']' :
 this.hostname
 );

test/parallel/test-url-format.js

@@ -148,6 +148,12 @@ const formatTests = {
 host: '[fedc:ba98:7654:3210:fedc:ba98:7654:3210]:61616',
 pathname: '/s/stopButton'
 },
+'http://[::]/': {
+href: 'http://[::]/',
+protocol: 'http:',
+hostname: '[::]',
+pathname: '/'
+},
 
 // Encode context-specific delimiters in path and query, but do not touch
 // other non-delimiter chars like `%`.