diff --git a/lib/url.js b/lib/url.js
index ea47a071b8f045..9c0b9248354ecd 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -22,48 +22,47 @@ function Url() {
   this.pathname = null;
   this.path = null;
   this.href = null;
+  this._prependSlash = false;
+  this._errored = false;
 }
 
 // Reference: RFC 3986, RFC 1808, RFC 2396
 
-// define these here so at least they only have to be
-// compiled once on the first module load.
-const protocolPattern = /^([a-z0-9.+-]+:)/i;
-const portPattern = /:[0-9]*$/;
-
-// Special case for a simple path URL
-const simplePathPattern = /^(\/\/?(?!\/)[^\?\s]*)(\?[^\s]*)?$/;
+const _protocolCharacters = makeAsciiTable([
+  [0x61, 0x7A]/*a-z*/,
+  [0x41, 0x5A]/*A-Z*/,
+  0x2E/*'.'*/, 0x2B/*'+'*/, 0x2D/*'-'*/
+]);
 
 // RFC 2396: characters reserved for delimiting URLs.
 // We actually just auto-escape these.
-const delims = ['<', '>', '"', '`', ' ', '\r', '\n', '\t'];
-
 // RFC 2396: characters not allowed for various reasons.
-const unwise = ['{', '}', '|', '\\', '^', '`'].concat(delims);
-
 // Allowed by RFCs, but cause of XSS attacks.  Always escape these.
-const autoEscape = ['\''].concat(unwise);
+const _autoEscape = [
+  '<', '>', '\'', '`', ' ', '\r', '\n', '\t', '{', '}', '|', '\\',
+  '^', '`', '"'
+];
 
-// Characters that are never ever allowed in a hostname.
-// Note that any invalid chars are also handled, but these
-// are the ones that are *expected* to be seen, so we fast-path them.
-const nonHostChars = ['%', '/', '?', ';', '#'].concat(autoEscape);
-const hostEndingChars = ['/', '?', '#'];
-const hostnameMaxLen = 255;
-const hostnamePartPattern = /^[+a-z0-9A-Z_-]{0,63}$/;
-const hostnamePartStart = /^([+a-z0-9A-Z_-]{0,63})(.*)$/;
-// protocols that can allow "unsafe" and "unwise" chars.
-const unsafeProtocol = {
-  'javascript': true,
-  'javascript:': true
-};
-// protocols that never have a hostname.
-const hostlessProtocol = {
-  'javascript': true,
-  'javascript:': true
-};
-// protocols that always contain a // bit.
-const slashedProtocol = {
+const _autoEscapeMap = new Array(128);
+
+for (let i = 0, len = _autoEscapeMap.length; i < len; ++i) {
+  _autoEscapeMap[i] = '';
+}
+
+for (let i = 0, len = _autoEscape.length; i < len; ++i) {
+  const c = _autoEscape[i];
+  let esc = encodeURIComponent(c);
+  if (esc === c)
+    esc = escape(c);
+  _autoEscapeMap[c.charCodeAt(0)] = esc;
+}
+
+// Same as autoEscapeMap except \ is not escaped but is turned into /.
+const _afterQueryAutoEscapeMap = _autoEscapeMap.slice();
+_autoEscapeMap[0x5C /*'\'*/] = '/';
+
+// Protocols that always contain a // bit.
+const _slashProtocols = {
   'http': true,
   'https': true,
   'ftp': true,
@@ -75,295 +74,138 @@ const slashedProtocol = {
   'gopher:': true,
   'file:': true
 };
+
+const _autoEscapeCharacters = makeAsciiTable(_autoEscape.map(function(v) {
+  return v.charCodeAt(0);
+}));
+
+// Characters that are never ever allowed in a hostname.
+// Note that any invalid chars are also handled, but these
+// are the ones that are *expected* to be seen, so we fast-path them.
+const _hostEndingCharacters = makeAsciiTable(
+    ['#', '?', '/', '\\', ';'].map(function(v) {
+      return v.charCodeAt(0);
+    }));
+// If these characters end a host name, the path will not be prepended a /.
+const _hostEndingCharactersNoPrependSlash = makeAsciiTable([
+  '<', '>', '"', '`', ' ', '\r', '\n', '\t', '{', '}', '|', '^', '`', '\'', '%'
+].map(function(v) {
+  return v.charCodeAt(0);
+}));
+
 const querystring = require('querystring');
 
 function urlParse(url, parseQueryString, slashesDenoteHost) {
-  if (url instanceof Url) return url;
+  if (url instanceof Url)
+    return url;
 
   var u = new Url();
   u.parse(url, parseQueryString, slashesDenoteHost);
+  // If we hit a parse error, return an empty object with the href only.
+  if (u._errored) {
+    u = new Url();
+    u.href = url;
+    u._errored = true;
+  } else {
+    u.href = u.format();
+  }
   return u;
 }
 
-Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
-  if (typeof url !== 'string') {
-    throw new TypeError('Parameter "url" must be a string, not ' + typeof url);
-  }
-
-  // Copy chrome, IE, opera backslash-handling behavior.
-  // Back slashes before the query string get converted to forward slashes
-  // See: https://code.google.com/p/chromium/issues/detail?id=25916
-  const queryIndex = url.indexOf('?');
-  const splitter =
-      (queryIndex !== -1 && queryIndex < url.indexOf('#')) ? '?' : '#';
-  const uSplit = url.split(splitter);
-  const slashRegex = /\\/g;
-  uSplit[0] = uSplit[0].replace(slashRegex, '/');
-  url = uSplit.join(splitter);
-
-  var rest = url;
-
-  // trim before proceeding.
-  // This is to support parse stuff like "  http://foo.com  \n"
-  rest = rest.trim();
-
-  if (!slashesDenoteHost && url.split('#').length === 1) {
-    // Try fast path regexp
-    var simplePath = simplePathPattern.exec(rest);
-    if (simplePath) {
-      this.path = rest;
-      this.href = rest;
-      this.pathname = simplePath[1];
-      if (simplePath[2]) {
-        this.search = simplePath[2];
-        if (parseQueryString) {
-          this.query = querystring.parse(this.search.substr(1));
-        } else {
-          this.query = this.search.substr(1);
-        }
-      } else if (parseQueryString) {
-        this.search = '';
-        this.query = {};
-      }
-      return this;
-    }
+Url.prototype.parse = function(str, parseQueryString, slashesDenoteHost) {
+  if (typeof str !== 'string') {
+    throw new TypeError(`Parameter 'url' must be a string, not ` +
+        typeof str);
   }
-
-  var proto = protocolPattern.exec(rest);
-  if (proto) {
-    proto = proto[0];
-    var lowerProto = proto.toLowerCase();
-    this.protocol = lowerProto;
-    rest = rest.substr(proto.length);
+  var start = 0;
+  var end = str.length - 1;
+
+  // Trim leading and trailing ws.
+  while (str.charCodeAt(start) <= 0x20 /*' '*/) start++;
+  var trimmedStart = start;
+  while (str.charCodeAt(end) <= 0x20 /*' '*/) end--;
+
+  start = this._parseProtocol(str, start, end);
+
+  // Javascript doesn't have host.
+  if (this.protocol !== 'javascript:') {
+    start = this._parseHost(str, trimmedStart, start, end, slashesDenoteHost);
+    var proto = this.protocol;
+    if (this._isEmpty(this.hostname) &&
+        (this.slashes || (!this._isEmpty(proto) && !_slashProtocols[proto])))
+      this.hostname = this.host = '';
   }
 
-  // figure out if it's got a host
-  // user@server is *always* interpreted as a hostname, and url
-  // resolution will treat //foo/bar as host=foo,path=bar because that's
-  // how the browser resolves relative URLs.
-  if (slashesDenoteHost || proto || rest.match(/^\/\/[^@\/]+@[^@\/]+/)) {
-    var slashes = rest.substr(0, 2) === '//';
-    if (slashes && !(proto && hostlessProtocol[proto])) {
-      rest = rest.substr(2);
-      this.slashes = true;
-    }
+  if (start <= end) {
+    var ch = str.charCodeAt(start);
+    if (ch === 0x2F /*'/'*/ || ch === 0x5C /*'\'*/)
+      this._parsePath(str, start, end);
+    else if (ch === 0x3F /*'?'*/)
+      this._parseQuery(str, start, end);
+    else if (ch === 0x23 /*'#'*/)
+      this._parseHash(str, start, end);
+    else if (this.protocol !== 'javascript:')
+      this._parsePath(str, start, end);
+    else // For javascript the pathname is just the rest of it.
+      this.pathname = str.slice(start, end + 1);
   }
 
-  if (!hostlessProtocol[proto] &&
-      (slashes || (proto && !slashedProtocol[proto]))) {
-
-    // there's a hostname.
-    // the first instance of /, ?, ;, or # ends the host.
-    //
-    // If there is an @ in the hostname, then non-host chars *are* allowed
-    // to the left of the last @ sign, unless some host-ending character
-    // comes *before* the @-sign.
-    // URLs are obnoxious.
-    //
-    // ex:
-    // http://a@b@c/ => user:a@b host:c
-    // http://a@b?@c => user:a host:b path:/?@c
-
-    // v0.12 TODO(isaacs): This is not quite how Chrome does things.
-    // Review our test case against browsers more comprehensively.
-
-    // find the first instance of any hostEndingChars
-    var hostEnd = -1;
-    for (let i = 0; i < hostEndingChars.length; i++) {
-      const hec = rest.indexOf(hostEndingChars[i]);
-      if (hec !== -1 && (hostEnd === -1 || hec < hostEnd))
-        hostEnd = hec;
-    }
-
-    // at this point, either we have an explicit point where the
-    // auth portion cannot go past, or the last @ char is the decider.
-    var auth, atSign;
-    if (hostEnd === -1) {
-      // atSign can be anywhere.
-      atSign = rest.lastIndexOf('@');
-    } else {
-      // atSign must be in auth portion.
-      // http://a@b/c@d => host:b auth:a path:/c@d
-      atSign = rest.lastIndexOf('@', hostEnd);
-    }
-
-    // Now we have a portion which is definitely the auth.
-    // Pull that off.
-    if (atSign !== -1) {
-      auth = rest.slice(0, atSign);
-      rest = rest.slice(atSign + 1);
-      this.auth = decodeURIComponent(auth);
-    }
-
-    // the host is the remaining to the left of the first non-host char
-    hostEnd = -1;
-    for (let i = 0; i < nonHostChars.length; i++) {
-      const hec = rest.indexOf(nonHostChars[i]);
-      if (hec !== -1 && (hostEnd === -1 || hec < hostEnd))
-        hostEnd = hec;
-    }
-    // if we still have not hit it, then the entire thing is a host.
-    if (hostEnd === -1)
-      hostEnd = rest.length;
-
-    this.host = rest.slice(0, hostEnd);
-    rest = rest.slice(hostEnd);
-
-    // pull out port.
-    this.parseHost();
-
-    // we've indicated that there is a hostname,
-    // so even if it's empty, it has to be present.
-    this.hostname = this.hostname || '';
-
-    // if hostname begins with [ and ends with ]
-    // assume that it's an IPv6 address.
-    var ipv6Hostname = this.hostname[0] === '[' &&
-        this.hostname[this.hostname.length - 1] === ']';
-
-    // validate a little.
-    if (!ipv6Hostname) {
-      var hostparts = this.hostname.split(/\./);
-      for (let i = 0, l = hostparts.length; i < l; i++) {
-        var part = hostparts[i];
-        if (!part) continue;
-        if (!part.match(hostnamePartPattern)) {
-          var newpart = '';
-          for (let j = 0, k = part.length; j < k; j++) {
-            if (part.charCodeAt(j) > 127) {
-              // we replace non-ASCII char with a temporary placeholder
-              // we need this to make sure size of hostname is not
-              // broken by replacing non-ASCII by nothing
-              newpart += 'x';
-            } else {
-              newpart += part[j];
-            }
-          }
-          // we test again with ASCII char only
-          if (!newpart.match(hostnamePartPattern)) {
-            var validParts = hostparts.slice(0, i);
-            var notHost = hostparts.slice(i + 1);
-            var bit = part.match(hostnamePartStart);
-            if (bit) {
-              validParts.push(bit[1]);
-              notHost.unshift(bit[2]);
-            }
-            if (notHost.length) {
-              rest = '/' + notHost.join('.') + rest;
-            }
-            this.hostname = validParts.join('.');
-            break;
-          }
-        }
-      }
-    }
-
-    if (this.hostname.length > hostnameMaxLen) {
-      this.hostname = '';
-    } else {
-      // hostnames are always lower case.
-      this.hostname = this.hostname.toLowerCase();
-    }
-
-    if (!ipv6Hostname) {
-      // IDNA Support: Returns a punycoded representation of "domain".
-      // It only converts parts of the domain name that
-      // have non-ASCII characters, i.e. it doesn't matter if
-      // you call it with a domain that already is ASCII-only.
-      this.hostname = punycode.toASCII(this.hostname);
-    }
+  if (this._isEmpty(this.pathname) &&
+      !this._isEmpty(this.hostname) &&
+      _slashProtocols[this.protocol])
+    this.pathname = '/';
 
-    var p = this.port ? ':' + this.port : '';
-    var h = this.hostname || '';
-    this.host = h + p;
+  var pathname = this.pathname;
+  var search = this.search;
 
-    // strip [ and ] from the hostname
-    // the host field still retains them, though
-    if (ipv6Hostname) {
-      this.hostname = this.hostname.substr(1, this.hostname.length - 2);
-      if (rest[0] !== '/') {
-        rest = '/' + rest;
-      }
-    }
-  }
-
-  // now rest is set to the post-host stuff.
-  // chop off any delim chars.
-  if (!unsafeProtocol[lowerProto]) {
-
-    // First, make 100% sure that any "autoEscape" chars get
-    // escaped, even if encodeURIComponent doesn't think they
-    // need to be.
-    for (let i = 0, l = autoEscape.length; i < l; i++) {
-      var ae = autoEscape[i];
-      if (rest.indexOf(ae) === -1)
-        continue;
-      var esc = encodeURIComponent(ae);
-      if (esc === ae) {
-        esc = escape(ae);
-      }
-      rest = rest.split(ae).join(esc);
-    }
-  }
+  if (this._isEmpty(search)) {
+    // Bug-to-bug compat.
+    if (parseQueryString)
+      this.search = '';
 
+    this.query = parseQueryString ? {} : search;
 
-  // chop off from the tail first.
-  var hash = rest.indexOf('#');
-  if (hash !== -1) {
-    // got a fragment string.
-    this.hash = rest.substr(hash);
-    rest = rest.slice(0, hash);
-  }
-  var qm = rest.indexOf('?');
-  if (qm !== -1) {
-    this.search = rest.substr(qm);
-    this.query = rest.substr(qm + 1);
-    if (parseQueryString) {
-      this.query = querystring.parse(this.query);
-    }
-    rest = rest.slice(0, qm);
-  } else if (parseQueryString) {
-    // no query string, but parseQueryString still requested
-    this.search = '';
-    this.query = {};
-  }
-  if (rest) this.pathname = rest;
-  if (slashedProtocol[lowerProto] &&
-      this.hostname && !this.pathname) {
-    this.pathname = '/';
+    if (!this._isEmpty(pathname))
+      this.path = pathname;
+  } else {
+    var query = search.slice(1);
+    this.query = parseQueryString ? querystring.parse(query) : query;
+    this.path = this._isEmpty(pathname) ? search : pathname + search;
   }
+};
 
-  //to support http.request
-  if (this.pathname || this.search) {
-    const p = this.pathname || '';
-    const s = this.search || '';
-    this.path = p + s;
-  }
+function urlResolve(source, relative) {
+  return urlParse(source, false, true).resolve(relative);
+}
 
-  // finally, reconstruct the href based on what has been validated.
-  this.href = this.format();
-  return this;
+Url.prototype.resolve = function(relative) {
+  return this.resolveObject(urlParse(relative, false, true)).format();
 };
 
-// format a parsed object into a url string
+// Format a parsed object into a url string.
 function urlFormat(obj) {
-  // ensure it's an object, and not a string url.
+  // Ensure it's an object, and not a string url.
   // If it's an obj, this is a no-op.
   // this way, you can call url_format() on strings
   // to clean up potentially wonky urls.
-  if (typeof obj === 'string') obj = urlParse(obj);
-
-  else if (typeof obj !== 'object' || obj === null)
-    throw new TypeError('Parameter "urlObj" must be an object, not ' +
+  if (typeof obj === 'string') {
+    obj = urlParse(obj);
+  } else if (typeof obj !== 'object' || obj === null) {
+    throw new TypeError('Parameter \'urlObj\' must be an object, not ' +
                         obj === null ? 'null' : typeof obj);
-
-  else if (!(obj instanceof Url)) return Url.prototype.format.call(obj);
+  } else if (!(obj instanceof Url)) {
+    return Url.prototype.format.call(obj);
+  }
 
   return obj.format();
 }
 
 Url.prototype.format = function() {
+  if (this._errored)
+    return this.href;
+
   var auth = this.auth || '';
+
   if (auth) {
     auth = encodeURIComponent(auth);
     auth = auth.replace(/%3A/i, ':');
@@ -373,110 +215,140 @@ Url.prototype.format = function() {
   var protocol = this.protocol || '';
   var pathname = this.pathname || '';
   var hash = this.hash || '';
-  var host = false;
+  var search = this.search || '';
   var query = '';
+  var hostname = this.hostname || '';
+  var port = this.port || '';
+  var host = false;
+  var scheme = '';
+
+  var q = this.query;
+  if (q !== null && typeof q === 'object')
+    query = querystring.stringify(q);
+
+  if (!search)
+    search = query ? '?' + query : '';
+
+  if (protocol && protocol.charCodeAt(protocol.length - 1) !== 0x3A /*':'*/)
+    protocol += ':';
 
   if (this.host) {
     host = auth + this.host;
-  } else if (this.hostname) {
-    host = auth + (this.hostname.indexOf(':') === -1 ?
-        this.hostname :
-        '[' + this.hostname + ']');
-    if (this.port) {
-      host += ':' + this.port;
-    }
-  }
-
-  if (this.query !== null &&
-      typeof this.query === 'object' &&
-      Object.keys(this.query).length) {
-    query = querystring.stringify(this.query);
+  } else if (hostname) {
+    if (containsCharacter2(hostname, 0x3A/*':'*/, -1))
+      hostname = '[' + hostname + ']';
+    host = auth + hostname + (port ? ':' + port : '');
   }
 
-  var search = this.search || (query && ('?' + query)) || '';
+  var slashes = this.slashes ||
+                ((!protocol || _slashProtocols[protocol]) && host !== false);
 
-  if (protocol && protocol.substr(-1) !== ':') protocol += ':';
+  if (protocol)
+    scheme = protocol + (slashes ? '//' : '');
+  else if (slashes)
+    scheme = '//';
 
-  // only the slashedProtocols get the //.  Not mailto:, xmpp:, etc.
-  // unless they had them to begin with.
-  if (this.slashes ||
-      (!protocol || slashedProtocol[protocol]) && host !== false) {
-    host = '//' + (host || '');
-    if (pathname && pathname.charAt(0) !== '/') pathname = '/' + pathname;
-  } else if (!host) {
-    host = '';
-  }
-
-  if (hash && hash.charAt(0) !== '#') hash = '#' + hash;
-  if (search && search.charAt(0) !== '?') search = '?' + search;
+  if (slashes && pathname && pathname.charCodeAt(0) !== 0x2F /*'/'*/)
+    pathname = '/' + pathname;
+  if (search && search.charCodeAt(0) !== 0x3F /*'?'*/)
+    search = '?' + search;
+  if (hash && hash.charCodeAt(0) !== 0x23 /*'#'*/)
+    hash = '#' + hash;
 
-  pathname = pathname.replace(/[?#]/g, function(match) {
-    return encodeURIComponent(match);
-  });
-  search = search.replace('#', '%23');
+  pathname = escapePathName(pathname);
+  search = escapeSearch(search);
 
-  return protocol + host + pathname + search + hash;
+  return scheme + (host === false ? '' : host) + pathname + search + hash;
 };
 
-function urlResolve(source, relative) {
-  return urlParse(source, false, true).resolve(relative);
-}
+Url.prototype._clone = function() {
+  var ret = new Url();
+  ret.protocol = this.protocol;
+  ret.slashes = this.slashes;
+  ret.auth = this.auth;
+  ret.host = this.host;
+  ret.port = this.port;
+  ret.hostname = this.hostname;
+  ret.hash = this.hash;
+  ret.search = this.search;
+  ret.query = this.query;
+  ret.pathname = this.pathname;
+  ret.path = this.path;
+  ret.href = this.href;
+  ret._prependSlash = this._prependSlash;
+  return ret;
+};
 
-Url.prototype.resolve = function(relative) {
-  return this.resolveObject(urlParse(relative, false, true)).format();
+Url.prototype._copyPropsTo = function(target, noProtocol) {
+  if (!noProtocol)
+    target.protocol = this.protocol;
+
+  target.slashes = this.slashes;
+  target.auth = this.auth;
+  target.host = this.host;
+  target.port = this.port;
+  target.hostname = this.hostname;
+  target.hash = this.hash;
+  target.search = this.search;
+  target.query = this.query;
+  target.pathname = this.pathname;
+  target.path = this.path;
+  target.href = this.href;
+  target._prependSlash = this._prependSlash;
 };
 
 function urlResolveObject(source, relative) {
-  if (!source) return relative;
+  if (!source)
+    return relative;
   return urlParse(source, false, true).resolveObject(relative);
 }
 
+Url.prototype._resolveEmpty = function() {
+  var ret = this._clone();
+  ret.hash = null;
+  ret.href = ret.format();
+  return ret;
+};
+
 Url.prototype.resolveObject = function(relative) {
   if (typeof relative === 'string') {
-    var rel = new Url();
-    rel.parse(relative, false, true);
-    relative = rel;
+    if (relative.length === 0)
+      return this._resolveEmpty();
+
+    var u = new Url();
+    u.parse(relative, false, true);
+    relative = u;
+  } else if (this._isEmpty(relative.href)) {
+    return this._resolveEmpty();
   }
 
-  var result = new Url();
-  var tkeys = Object.keys(this);
-  for (var tk = 0; tk < tkeys.length; tk++) {
-    var tkey = tkeys[tk];
-    result[tkey] = this[tkey];
-  }
+  // If there was an error parsing the relative url,
+  // we just return it entirely.
+  if (relative._errored)
+    return relative;
 
-  // hash is always overridden, no matter what.
-  // even href="" will remove it.
-  result.hash = relative.hash;
+  var result = this._clone();
 
-  // if the relative url is empty, then there's nothing left to do here.
-  if (relative.href === '') {
-    result.href = result.format();
-    return result;
-  }
+  // Hash is always overridden, no matter what.
+  // even href='' will remove it.
+  result.hash = relative.hash;
 
-  // hrefs like //foo/bar always cut to the protocol.
-  if (relative.slashes && !relative.protocol) {
-    // take everything except the protocol from relative
-    var rkeys = Object.keys(relative);
-    for (var rk = 0; rk < rkeys.length; rk++) {
-      var rkey = rkeys[rk];
-      if (rkey !== 'protocol')
-        result[rkey] = relative[rkey];
-    }
+  // Hrefs like //foo/bar always cut to the protocol.
+  if (relative.slashes && this._isEmpty(relative.protocol)) {
+    relative._copyPropsTo(result, true);
 
-    //urlParse appends trailing / to urls like http://www.example.com
-    if (slashedProtocol[result.protocol] &&
-        result.hostname && !result.pathname) {
+    if (_slashProtocols[result.protocol] &&
+        !this._isEmpty(result.hostname) &&
+        this._isEmpty(result.pathname))
       result.path = result.pathname = '/';
-    }
 
     result.href = result.format();
     return result;
   }
 
-  if (relative.protocol && relative.protocol !== result.protocol) {
-    // if it's a known url protocol, then changing
+  if (!this._isEmpty(relative.protocol) &&
+      relative.protocol !== result.protocol) {
+    // If it's a known url protocol, then changing
     // the protocol does weird things
     // first, if it's not file:, then we MUST have a host,
     // and if there was a path
@@ -484,30 +356,31 @@ Url.prototype.resolveObject = function(relative) {
     // if it is file:, then the host is dropped,
     // because that's known to be hostless.
     // anything else is assumed to be absolute.
-    if (!slashedProtocol[relative.protocol]) {
-      var keys = Object.keys(relative);
-      for (var v = 0; v < keys.length; v++) {
-        var k = keys[v];
-        result[k] = relative[k];
-      }
+    if (!_slashProtocols[relative.protocol]) {
+      relative._copyPropsTo(result, false);
       result.href = result.format();
       return result;
     }
 
     result.protocol = relative.protocol;
-    if (!relative.host &&
+    if (this._isEmpty(relative.host) &&
         !/^file:?$/.test(relative.protocol) &&
-        !hostlessProtocol[relative.protocol]) {
+        relative.protocol !== 'javascript:') {
       const relPath = (relative.pathname || '').split('/');
       while (relPath.length && !(relative.host = relPath.shift()));
-      if (!relative.host) relative.host = '';
-      if (!relative.hostname) relative.hostname = '';
-      if (relPath[0] !== '') relPath.unshift('');
-      if (relPath.length < 2) relPath.unshift('');
+      if (this._isEmpty(relative.host))
+        relative.host = '';
+      if (this._isEmpty(relative.hostname))
+        relative.hostname = '';
+      if (relPath[0] !== '')
+        relPath.unshift('');
+      if (relPath.length < 2)
+        relPath.unshift('');
       result.pathname = relPath.join('/');
     } else {
       result.pathname = relative.pathname;
     }
+
     result.search = relative.search;
     result.query = relative.query;
     result.host = relative.host || '';
@@ -525,19 +398,29 @@ Url.prototype.resolveObject = function(relative) {
     return result;
   }
 
-  const isSourceAbs = (result.pathname && result.pathname.charAt(0) === '/');
+  const isSourceAbs =
+      (!this._isEmpty(result.pathname) &&
+      result.pathname.charCodeAt(0) === 0x2F /*'/'*/);
   const isRelAbs = (
-      relative.host ||
-      relative.pathname && relative.pathname.charAt(0) === '/'
-  );
-  var mustEndAbs = (isRelAbs || isSourceAbs ||
-                    (result.host && relative.pathname));
+      !this._isEmpty(relative.host) ||
+      (!this._isEmpty(relative.pathname) &&
+      relative.pathname.charCodeAt(0) === 0x2F /*'/'*/));
+
+  let mustEndAbs = (isRelAbs ||
+                    isSourceAbs ||
+                    (!this._isEmpty(result.host) &&
+                    !this._isEmpty(relative.pathname)));
+
   const removeAllDots = mustEndAbs;
-  let srcPath = result.pathname && result.pathname.split('/') || [];
-  const relPath = relative.pathname && relative.pathname.split('/') || [];
-  const psychotic = result.protocol && !slashedProtocol[result.protocol];
 
-  // if the url is a non-slashed url, then relative
+  let srcPath = !this._isEmpty(result.pathname) &&
+      result.pathname.split('/') || [];
+  const relPath = !this._isEmpty(relative.pathname) &&
+      relative.pathname.split('/') || [];
+  const psychotic = !this._isEmpty(result.protocol) &&
+      !_slashProtocols[result.protocol];
+
+  // If the url is a non-slashed url, then relative
   // links like ../.. should be able
   // to crawl up to the hostname, as well.  This is strange.
   // result.protocol has already been set by now.
@@ -545,135 +428,131 @@ Url.prototype.resolveObject = function(relative) {
   if (psychotic) {
     result.hostname = '';
     result.port = null;
-    if (result.host) {
-      if (srcPath[0] === '') srcPath[0] = result.host;
-      else srcPath.unshift(result.host);
+    if (!this._isEmpty(result.host)) {
+      if (srcPath[0] === '')
+        srcPath[0] = result.host;
+      else
+        srcPath.unshift(result.host);
     }
     result.host = '';
-    if (relative.protocol) {
+    if (!this._isEmpty(relative.protocol)) {
       relative.hostname = null;
       relative.port = null;
       if (relative.host) {
-        if (relPath[0] === '') relPath[0] = relative.host;
-        else relPath.unshift(relative.host);
+        if (relPath[0] === '')
+          relPath[0] = relative.host;
+        else
+          relPath.unshift(relative.host);
       }
-      relative.host = null;
+      relative.host = '';
     }
     mustEndAbs = mustEndAbs && (relPath[0] === '' || srcPath[0] === '');
   }
 
   if (isRelAbs) {
     // it's absolute.
-    result.host = (relative.host || relative.host === '') ?
-                  relative.host : result.host;
-    result.hostname = (relative.hostname || relative.hostname === '') ?
-                      relative.hostname : result.hostname;
+    result.host = !this._isEmpty(relative.host) ? relative.host : result.host;
+    result.hostname =
+        !this._isEmpty(relative.hostname) ? relative.hostname : result.hostname;
     result.search = relative.search;
     result.query = relative.query;
     srcPath = relPath;
-    // fall through to the dot-handling below.
+    // Fall through to the dot-handling below.
   } else if (relPath.length) {
-    // it's relative
+    // It's relative
     // throw away the existing file, and take the new path instead.
-    if (!srcPath) srcPath = [];
+    if (!srcPath)
+      srcPath = [];
     srcPath.pop();
     srcPath = srcPath.concat(relPath);
     result.search = relative.search;
     result.query = relative.query;
-  } else if (relative.search !== null && relative.search !== undefined) {
-    // just pull out the search.
+  } else if (!this._isEmpty(relative.search)) {
+    // Just pull out the search.
     // like href='?foo'.
     // Put this after the other two cases because it simplifies the booleans
     if (psychotic) {
       result.hostname = result.host = srcPath.shift();
-      //occasionally the auth can get stuck only in host
-      //this especially happens in cases like
-      //url.resolveObject('mailto:local1@domain1', 'local2@domain2')
-      const authInHost = result.host && result.host.indexOf('@') > 0 ?
-                       result.host.split('@') : false;
-      if (authInHost) {
+      // Occasionally the auth can get stuck only in host
+      // this especially happens in cases like
+      // url.resolveObject('mailto:local1@domain1', 'local2@domain2').
+      const authInHost = !this._isEmpty(result.host) &&
+          result.host.indexOf('@') > 0 ? result.host.split('@') : false;
+      if (authInHost !== false) {
         result.auth = authInHost.shift();
         result.host = result.hostname = authInHost.shift();
       }
     }
     result.search = relative.search;
     result.query = relative.query;
-    //to support http.request
-    if (result.pathname !== null || result.search !== null) {
-      result.path = (result.pathname ? result.pathname : '') +
-                    (result.search ? result.search : '');
-    }
+    result.path = result.pathname !== null ?
+        result.pathname + result.search : result.search;
     result.href = result.format();
     return result;
   }
 
   if (!srcPath.length) {
-    // no path at all.  easy.
+    // No path at all.  easy.
     // we've already handled the other stuff above.
     result.pathname = null;
-    //to support http.request
-    if (result.search) {
-      result.path = '/' + result.search;
-    } else {
-      result.path = null;
-    }
+    result.path = this._isEmpty(result.search) ? null : '/' + result.search;
     result.href = result.format();
     return result;
   }
 
-  // if a url ENDs in . or .., then it must get a trailing slash.
+  // If a url ENDs in . or .., then it must get a trailing slash.
   // however, if it ends in anything else non-slashy,
   // then it must NOT get a trailing slash.
   var last = srcPath.slice(-1)[0];
   var hasTrailingSlash = (
-      (result.host || relative.host || srcPath.length > 1) &&
+      (!this._isEmpty(result.host) ||
+      !this._isEmpty(relative.host) ||
+      srcPath.length > 1) &&
       (last === '.' || last === '..') || last === '');
 
-  // strip single dots, resolve double dots to parent dir
-  // if the path tries to go above the root, `up` ends up > 0
+  // Strip single dots, resolve double dots to parent dir
+  // if the path tries to go above the root, `up` ends up > 0.
   var up = 0;
   for (let i = srcPath.length; i >= 0; i--) {
     last = srcPath[i];
     if (last === '.') {
-      spliceOne(srcPath, i);
+      srcPath.splice(i, 1);
     } else if (last === '..') {
-      spliceOne(srcPath, i);
+      srcPath.splice(i, 1);
       up++;
     } else if (up) {
-      spliceOne(srcPath, i);
+      srcPath.splice(i, 1);
       up--;
     }
   }
 
-  // if the path is allowed to go above the root, restore leading ..s
+  // If the path is allowed to go above the root, restore leading ..s.
   if (!mustEndAbs && !removeAllDots) {
-    for (; up--; up) {
+    for (; up--; up)
       srcPath.unshift('..');
-    }
   }
 
   if (mustEndAbs && srcPath[0] !== '' &&
-      (!srcPath[0] || srcPath[0].charAt(0) !== '/')) {
+      (!srcPath[0] || srcPath[0].charCodeAt(0) !== 0x2F /*'/'*/)) {
     srcPath.unshift('');
   }
 
-  if (hasTrailingSlash && (srcPath.join('/').substr(-1) !== '/')) {
+  if (hasTrailingSlash && (srcPath.join('/').substr(-1) !== '/'))
     srcPath.push('');
-  }
 
   var isAbsolute = srcPath[0] === '' ||
-      (srcPath[0] && srcPath[0].charAt(0) === '/');
+      (srcPath[0] && srcPath[0].charCodeAt(0) === 0x2F /*'/'*/);
 
   // put the host back
   if (psychotic) {
     result.hostname = result.host = isAbsolute ? '' :
-                                    srcPath.length ? srcPath.shift() : '';
-    //occasionally the auth can get stuck only in host
-    //this especially happens in cases like
-    //url.resolveObject('mailto:local1@domain1', 'local2@domain2')
-    const authInHost = result.host && result.host.indexOf('@') > 0 ?
-                     result.host.split('@') : false;
-    if (authInHost) {
+        srcPath.length ? srcPath.shift() : '';
+    // Occasionally the auth can get stuck only in host
+    // this especially happens in cases like
+    // url.resolveObject('mailto:local1@domain1', 'local2@domain2').
+    const authInHost = !this._isEmpty(result.host) &&
+        result.host.indexOf('@') > 0 ? result.host.split('@') : false;
+    if (authInHost !== false) {
       result.auth = authInHost.shift();
       result.host = result.hostname = authInHost.shift();
     }
@@ -681,44 +560,444 @@ Url.prototype.resolveObject = function(relative) {
 
   mustEndAbs = mustEndAbs || (result.host && srcPath.length);
 
-  if (mustEndAbs && !isAbsolute) {
+  if (mustEndAbs && !isAbsolute)
     srcPath.unshift('');
-  }
 
-  if (!srcPath.length) {
+  if (srcPath.length === 0) {
     result.pathname = null;
-    result.path = null;
+    result.path = this._isEmpty(result.search) ? null : result.search;
   } else {
-    result.pathname = srcPath.join('/');
+    var pathname = srcPath.join('/');
+    result.pathname = pathname;
+    result.path =
+        this._isEmpty(result.search) ? pathname : pathname + result.search;
   }
 
-  //to support request.http
-  if (result.pathname !== null || result.search !== null) {
-    result.path = (result.pathname ? result.pathname : '') +
-                  (result.search ? result.search : '');
-  }
   result.auth = relative.auth || result.auth;
   result.slashes = result.slashes || relative.slashes;
   result.href = result.format();
   return result;
 };
 
-Url.prototype.parseHost = function() {
-  var host = this.host;
-  var port = portPattern.exec(host);
-  if (port) {
-    port = port[0];
-    if (port !== ':') {
-      this.port = port.substr(1);
+Url.prototype._parseProtocol = function(str, start, end) {
+  var needsLowerCasing = false;
+  var protocolCharacters = _protocolCharacters;
+
+  for (var i = start; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+
+    if (ch === 0x3A /*':'*/) {
+      if (i - start === 0)
+        return start;
+      var protocol = str.slice(start, i + 1);
+      if (needsLowerCasing)
+        protocol = protocol.toLowerCase();
+      this.protocol = protocol;
+      return i + 1;
+    } else if (protocolCharacters[ch] === 1) {
+      if (ch < 0x61 /*'a'*/)
+        needsLowerCasing = true;
+    } else {
+      return start;
+    }
+
+  }
+  return start;
+};
+
+Url.prototype._parseAuth = function(str, start, end, decode) {
+  var auth = str.slice(start, end + 1);
+  if (decode)
+    auth = decodeURIComponent(auth);
+  this.auth = auth;
+};
+
+Url.prototype._parsePort = function(str, start, end) {
+  for (var i = start; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+
+    if (!(0x30 /*'0'*/ <= ch && ch <= 0x39 /*'9'*/)) {
+      this._prependSlash = true;
+      return false;
+    }
+  }
+
+  if (i > start)
+    this.port = str.slice(start, i);
+  return true;
+};
+
+Url.prototype._parseHost = function(str,
+                                    trimmedStart,
+                                    start,
+                                    end,
+                                    slashesDenoteHost) {
+  var hostEndingCharacters = _hostEndingCharacters;
+  var first = str.charCodeAt(start);
+  var second = str.charCodeAt(start + 1);
+  if ((first === 0x2F /*'/'*/ || first === 0x5C /*'\'*/) &&
+      (second === 0x2F /*'/'*/ || second === 0x5C /*'\'*/)) {
+    this.slashes = true;
+
+    // The string starts with // or \\.
+    if (start === trimmedStart) {
+      // The string is just '//' or '\\'.
+      if (end - start === 1)
+        return start;
+      // If slashes do not denote host and there is no auth,
+      // there is no host when the string starts with // or \\.
+      var hasAuth =
+          containsCharacter(str,
+                            0x40/*'@'*/,
+                            trimmedStart + 2,
+                            hostEndingCharacters);
+      if (!hasAuth && !slashesDenoteHost) {
+        this.slashes = null;
+        return start;
+      }
+    }
+    // There is a host that starts after the //.
+    start += 2;
+  }
+  // If there is no slashes, there is no hostname if
+  // 1. there was no protocol at all.
+  else if (this.protocol === null ||
+      // 2. there was a protocol that requires slashes
+      // e.g. in 'http:asd' 'asd' is not a hostname.
+      _slashProtocols[this.protocol]
+  ) {
+    return start;
+  }
+
+  var needsLowerCasing = false;
+  var idna = false;
+  var hostNameStart = start;
+  var hostnameEnd = end;
+  var lastCh = -1;
+  var hostEndsAtPortEnd = true;
+  var portStart = -1;
+  var charsAfterDot = 0;
+  var authNeedsDecoding = false;
+
+  var i;
+  var j = -1;
+
+  // Find the last occurrence of an @-sign until hostending character is met
+  // also mark if decoding is needed for the auth portion.
+  for (i = start; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+    if (ch === 0x40 /*'@'*/)
+      j = i;
+    else if (ch === 0x25 /*'%'*/)
+      authNeedsDecoding = true;
+    else if (hostEndingCharacters[ch] === 1)
+      break;
+  }
+
+  // @-sign was found at index j, everything to the left from it
+  // is auth part.
+  if (j > -1) {
+    this._parseAuth(str, start, j - 1, authNeedsDecoding);
+    // Hostname starts after the last @-sign-
+    start = hostNameStart = j + 1;
+  }
+
+  var hostEndingCharactersNoPrependSlash = _hostEndingCharactersNoPrependSlash;
+  // Host name is starting with a [.
+  if (str.charCodeAt(start) === 0x5B /*'['*/) {
+    for (let i = start + 1; i <= end; ++i) {
+      const ch = str.charCodeAt(i);
+
+      // Assume valid IP6 is between the brackets.
+      if (ch === 0x5D /*']'*/) {
+        var ip6End = i;
+        for (i = i + 1; i <= end; ++i) {
+          const ch = str.charCodeAt(i);
+          if (ch === 0x3A /*':'*/)
+            portStart = i + 1;
+          else if (hostEndingCharacters[ch] === 1 ||
+                   hostEndingCharactersNoPrependSlash[ch] === 1)
+            break;
+        }
+
+        const portEnd = i - 1;
+        hostnameEnd = portStart !== -1 ? portStart - 1 : ip6End + 1;
+
+        var isInvalidHost = portStart !== -1 && ip6End + 1 !== portStart - 1;
+        var hostname =
+            isInvalidHost ? str.slice(start, hostnameEnd).toLowerCase() :
+                str.slice(start + 1, hostnameEnd - 1).toLowerCase();
+
+        if (portStart !== -1)
+          hostEndsAtPortEnd = this._parsePort(str, portStart, portEnd);
+
+        this.hostname = hostname;
+
+        if (!isInvalidHost)
+          hostname = '[' + hostname + ']';
+
+        this.host =
+            this._isEmpty(this.port) ? hostname : hostname + ':' + this.port;
+        this.pathname = '/';
+        return (hostEndsAtPortEnd ? portEnd + 1 : portStart - 1);
+      }
+    }
+    // Empty hostname, [ starts a path.
+    return start;
+  }
+
+  for (i = start; i <= end; ++i) {
+    if (charsAfterDot > 62) {
+      this.hostname = this.host = str.slice(start, i);
+      return i;
+    }
+    const ch = str.charCodeAt(i);
+
+    if (ch === 0x3A /*':'*/) {
+      if (portStart !== -1) {
+        // Illegal character in port
+        this._errored = true;
+        return start;
+      }
+      portStart = i + 1;
+    } else if (ch < 0x61 /*'a'*/) {
+      if (ch === 0x2E /*'.'*/) {
+        // TODO(petkaantonov) This error is originally ignored:
+        // if (lastCh === 0x2E /*'.'*/ || lastCh === -1) {
+        //   this.hostname = this.host = '';
+        //   return start;
+        // }
+        charsAfterDot = -1;
+      } else if (0x41 /*'A'*/ <= ch && ch <= 0x5A /*'Z'*/) {
+        needsLowerCasing = true;
+      }
+      // Valid characters other than ASCII letters -, _, +, 0-9.
+      else if (!(ch === 0x2D /*'-'*/ ||
+              ch === 0x5F /*'_'*/ ||
+              ch === 0x2B /*'+'*/ ||
+              (0x30 /*'0'*/ <= ch && ch <= 0x39 /*'9'*/))) {
+        if (hostEndingCharacters[ch] === 0 &&
+            hostEndingCharactersNoPrependSlash[ch] === 0)
+          this._prependSlash = true;
+        hostnameEnd = i - 1;
+        break;
+      }
+    } else if (ch >= 0x7B /*'{'*/) {
+      if (ch <= 0x7E /*'~'*/) {
+        if (hostEndingCharactersNoPrependSlash[ch] === 0)
+          this._prependSlash = true;
+        hostnameEnd = i - 1;
+        break;
+      }
+      idna = true;
+      needsLowerCasing = true;
+    }
+    lastCh = ch;
+    charsAfterDot++;
+  }
+
+  const portEnd = i - 1;
+  hostnameEnd = portStart !== -1 ? portStart - 2 : hostnameEnd;
+
+  if (portStart !== -1)
+    hostEndsAtPortEnd = this._parsePort(str, portStart, portEnd);
+
+  // TODO(petkaantonov) This error is originally ignored:
+  // if (lastCh === 0x2E /*'.'*/)
+  //   hostnameEnd--
+
+  if (hostnameEnd + 1 !== start &&
+      hostnameEnd - hostNameStart <= 256) {
+    let hostname = str.slice(hostNameStart, hostnameEnd + 1);
+    if (needsLowerCasing)
+      hostname = hostname.toLowerCase();
+    if (idna)
+      hostname = punycode.toASCII(hostname);
+
+    this.hostname = hostname;
+    this.host =
+        this._isEmpty(this.port) ? hostname : hostname + ':' + this.port;
+  }
+
+  return (hostEndsAtPortEnd ? portEnd + 1 : portStart - 1);
+};
+
+Url.prototype._parsePath = function(str, start, end) {
+  var pathStart = start;
+  var pathEnd = end;
+  var escape = false;
+  var autoEscapeCharacters = _autoEscapeCharacters;
+
+  for (var i = start; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+
+    if (ch === 0x23 /*'#'*/) {
+      this._parseHash(str, i, end);
+      pathEnd = i - 1;
+      break;
+    } else if (ch === 0x3F /*'?'*/) {
+      this._parseQuery(str, i, end);
+      pathEnd = i - 1;
+      break;
+    } else if (!escape && autoEscapeCharacters[ch] === 1) {
+      escape = true;
+    }
+  }
+
+  if (pathStart > pathEnd) {
+    this.pathname = '/';
+    return;
+  }
+
+  var path;
+  if (escape)
+    path = getComponentEscaped(str, pathStart, pathEnd, false);
+  else
+    path = str.slice(pathStart, pathEnd + 1);
+
+  this.pathname = (this._prependSlash ? '/' + path : path);
+};
+
+Url.prototype._parseQuery = function(str, start, end) {
+  var queryStart = start;
+  var queryEnd = end;
+  var escape = false;
+  var autoEscapeCharacters = _autoEscapeCharacters;
+
+  for (var i = start; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+
+    if (ch === 0x23 /*'#'*/) {
+      this._parseHash(str, i, end);
+      queryEnd = i - 1;
+      break;
+    } else if (!escape && autoEscapeCharacters[ch] === 1) {
+      escape = true;
     }
-    host = host.substr(0, host.length - port.length);
   }
-  if (host) this.hostname = host;
+
+  if (queryStart > queryEnd) {
+    this.search = '';
+    return;
+  }
+
+  var query = escape ?
+      getComponentEscaped(str, queryStart, queryEnd, true) :
+      str.slice(queryStart, queryEnd + 1);
+
+  this.search = query;
+};
+
+Url.prototype._parseHash = function(str, start, end) {
+  if (start > end) {
+    this.hash = '';
+    return;
+  }
+  this.hash = getComponentEscaped(str, start, end, true);
+};
+
+// This must be a method because this getting inlined is crucial.
+Url.prototype._isEmpty = function(value) {
+  return value === null || value === '' || value === undefined;
 };
 
-// About 1.5x faster than the two-arg version of Array#splice().
-function spliceOne(list, index) {
-  for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1)
-    list[i] = list[k];
-  list.pop();
+// Search `char1` (integer code for a character) in `string`
+// starting from `fromIndex` and ending at `string.length - 1`
+// or when a stop character is found.
+function containsCharacter(string, char1, fromIndex, stopCharacterTable) {
+  var len = string.length;
+  for (var i = fromIndex; i < len; ++i) {
+    var ch = string.charCodeAt(i);
+
+    if (ch === char1)
+      return true;
+    else if (stopCharacterTable[ch] === 1)
+      return false;
+  }
+  return false;
+}
+
+// See if `char1` or `char2` (integer codes for characters)
+// is contained in `string`.
+function containsCharacter2(string, char1, char2) {
+  for (var i = 0, len = string.length; i < len; ++i) {
+    var ch = string.charCodeAt(i);
+    if (ch === char1 || ch === char2)
+      return true;
+  }
+  return false;
+}
+
+// Makes an array of 128 uint8's which represent boolean values.
+// Spec is an array of ascii code points or ascii code point ranges
+// ranges are expressed as [start, end].
+
+// For example, to create a table with the characters
+// 0x30-0x39 (decimals '0' - '9') and
+// 0x7A (lowercaseletter 'z') as `true`:
+
+// var a = makeAsciiTable([[0x30, 0x39], 0x7A]);
+// a[0x30]; //1
+// a[0x15]; //0
+// a[0x35]; //1
+function makeAsciiTable(spec) {
+  var ret = new Uint8Array(128);
+  spec.forEach(function(item) {
+    if (typeof item === 'number') {
+      ret[item] = 1;
+    } else {
+      var start = item[0];
+      var end = item[1];
+      for (var j = start; j <= end; ++j) {
+        ret[j] = 1;
+      }
+    }
+  });
+
+  return ret;
+}
+
+function escapePathName(pathname) {
+  if (!containsCharacter2(pathname, 0x23/*'#'*/, 0x3F /*'?'*/))
+    return pathname;
+
+  return pathname.replace(/[?#]/g, function(match) {
+    return encodeURIComponent(match);
+  });
 }
+
+function escapeSearch(search) {
+  if (!containsCharacter2(search, 0x23/*'#'*/, -1))
+    return search;
+
+  return search.replace(/#/g, function(match) {
+    return encodeURIComponent(match);
+  });
+}
+
+function getComponentEscaped(str, start, end, isAfterQuery) {
+  var cur = start;
+  var i = start;
+  var ret = '';
+  var autoEscapeMap = isAfterQuery ? _afterQueryAutoEscapeMap : _autoEscapeMap;
+  for (; i <= end; ++i) {
+    var ch = str.charCodeAt(i);
+    var escaped = autoEscapeMap[ch];
+
+    if (escaped !== '' && escaped !== undefined) {
+      if (cur < i)
+        ret += str.slice(cur, i);
+      ret += escaped;
+      cur = i + 1;
+    }
+  }
+  if (cur < i + 1)
+    ret += str.slice(cur, i);
+  return ret;
+}
+
+// Optimize back from normalized object caused by non-identifier keys.
+function FakeConstructor() {}
+FakeConstructor.prototype = _slashProtocols;
+/*jshint nonew: false */
+new FakeConstructor();
diff --git a/test/parallel/test-url.js b/test/parallel/test-url.js
index 95bde7b861e668..b8b249191a2625 100644
--- a/test/parallel/test-url.js
+++ b/test/parallel/test-url.js
@@ -861,10 +861,12 @@ for (const u in parseTests) {
   const spaced = url.parse(`     \t  ${u}\n\t`);
   let expected = parseTests[u];
 
-  Object.keys(actual).forEach(function(i) {
-    if (expected[i] === undefined && actual[i] === null) {
+  Object.keys(actual).forEach(function (i) {
+    // Private properties starting with _ don't need to be checked.
+    if (i.charAt(0) === "_")
+      expected[i] = actual[i];
+    else if (expected[i] === undefined && actual[i] === null)
       expected[i] = null;
-    }
   });
 
   assert.deepEqual(actual, expected);
@@ -932,9 +934,11 @@ for (const u in parseTestsWithQueryString) {
   const actual = url.parse(u, true);
   const expected = parseTestsWithQueryString[u];
   for (const i in actual) {
-    if (actual[i] === null && expected[i] === undefined) {
+    // Private properties starting with _ don't need to be checked.
+    if (i.charAt(0) === '_')
+      Object.defineProperty(expected, i, {enumerable: actual.propertyIsEnumerable(i), value: actual[i]});
+    else if (expected[i] === undefined && actual[i] === null)
       expected[i] = null;
-    }
   }
 
   assert.deepEqual(actual, expected);
@@ -1547,6 +1551,11 @@ relativeTests2.forEach(function(relativeTest) {
   var actual = url.resolveObject(url.parse(relativeTest[1]), relativeTest[0]);
   var expected = url.parse(relativeTest[2]);
 
+  Object.keys(actual).forEach(function(i) {
+    if (i.charAt(0) === '_')
+      expected[i] = actual[i];
+  });
+
   assert.deepEqual(actual, expected);
 
   expected = relativeTest[2];
@@ -1572,3 +1581,1423 @@ for (let i = 0; i < throws.length; i++) {
 }
 assert(url.format('') === '');
 assert(url.format({}) === '');
+
+var uri = url.parse('https://registry.lvh.me:8661/');
+delete uri.protocol;
+assert(uri.format() === '//registry.lvh.me:8661/');
+
+//
+// WhatWG Tests
+//
+
+// base = base url to use.
+// input = relative url that will be resolved in relation to base
+// nodejs = result given by node.js 0.12, usually incorrect so not optimal
+// override = custom override that differs from node.js but is more correct
+var whatwgTests = [
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://example\t.\norg',
+    'nodejs': 'http://example/%09.%0Aorg'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://user:pass@foo:21/bar;par?b#c',
+    'nodejs': 'http://user:pass@foo:21/bar;par?b#c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:foo.com',
+    'nodejs': 'http://example.org/foo/foo.com'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '\t   :foo.com   \n',
+    'nodejs': 'http://example.org/foo/:foo.com'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ' foo.com  ',
+    'nodejs': 'http://example.org/foo/foo.com'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'a:\t foo.com',
+    'nodejs': 'a:%09%20foo.com'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:21/ b ? d # e ',
+    'nodejs': 'http://f:21/%20b%20?%20d%20#%20e'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:/c',
+    'nodejs': 'http://f/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:0/c',
+    'nodejs': 'http://f:0/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:00000000000000/c',
+    'nodejs': 'http://f:00000000000000/c',
+    // 'override': 'http://f:0/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:00000000000000000000080/c',
+    'nodejs': 'http://f:00000000000000000000080/c',
+    // 'override': 'http://f/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:b/c',
+    'nodejs': 'http://f/:b/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f: /c',
+    'nodejs': 'http://f/%20/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:\n/c',
+    'nodejs': 'http://f/%0A/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:fifty-two/c',
+    'nodejs': 'http://f/:fifty-two/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f:999999/c',
+    'nodejs': 'http://f:999999/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://f: 21 / b ? d # e ',
+    'nodejs': 'http://f/%2021%20/%20b%20?%20d%20#%20e'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '',
+    'nodejs': 'http://example.org/foo/bar'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '  \t',
+    'nodejs': 'http://example.org/foo/bar'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':foo.com/',
+    'nodejs': 'http://example.org/foo/:foo.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':foo.com\\',
+    'nodejs': 'http://example.org/foo/:foo.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':',
+    'nodejs': 'http://example.org/foo/:'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':a',
+    'nodejs': 'http://example.org/foo/:a'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':/',
+    'nodejs': 'http://example.org/foo/:/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':\\',
+    'nodejs': 'http://example.org/foo/:/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':#',
+    'nodejs': 'http://example.org/foo/:#'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '#',
+    'nodejs': 'http://example.org/foo/bar#'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '#/',
+    'nodejs': 'http://example.org/foo/bar#/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '#\\',
+    'nodejs': 'http://example.org/foo/bar#%5C'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '#;?',
+    'nodejs': 'http://example.org/foo/bar#;?'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '?',
+    'nodejs': 'http://example.org/foo/bar?'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/',
+    'nodejs': 'http://example.org/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': ':23',
+    'nodejs': 'http://example.org/foo/:23'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/:23',
+    'nodejs': 'http://example.org/:23'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '::',
+    'nodejs': 'http://example.org/foo/::'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '::23',
+    'nodejs': 'http://example.org/foo/::23'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo://',
+    'nodejs': 'foo://'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://a:b@c:29/d',
+    'nodejs': 'http://a:b@c:29/d'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http::@c:29',
+    'nodejs': 'http://example.org/foo/:@c:29'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://&a:foo(b]c@d:2/',
+    'nodejs': 'http://%26a:foo(b%5Dc@d:2/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://::@c@d:2',
+    'nodejs': 'http://:%3A%40c@d:2/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://foo.com:b@d/',
+    'nodejs': 'http://foo.com:b@d/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://foo.com/\\@',
+    'nodejs': 'http://foo.com//@'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:\\\\foo.com\\',
+    'nodejs': 'http://foo.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:\\\\a\\b:c\\d@foo.com\\',
+    'nodejs': 'http://a/b:c/d@foo.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo:/',
+    'nodejs': 'foo:/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo:/bar.com/',
+    'nodejs': 'foo:/bar.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo://///////',
+    'nodejs': 'foo://///////'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo://///////bar.com/',
+    'nodejs': 'foo://///////bar.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'foo:////://///',
+    'nodejs': 'foo:////://///'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'c:/foo',
+    'nodejs': 'c:/foo'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '//foo/bar',
+    'nodejs': 'http://foo/bar'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://foo/path;a??e#f#g',
+    'nodejs': 'http://foo/path;a??e#f#g'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://foo/abcd?efgh?ijkl',
+    'nodejs': 'http://foo/abcd?efgh?ijkl'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://foo/abcd#foo?bar',
+    'nodejs': 'http://foo/abcd#foo?bar'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '[61:24:74]:98',
+    'nodejs': 'http://example.org/foo/[61:24:74]:98'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:[61:27]/:foo',
+    'nodejs': 'http://example.org/foo/[61:27]/:foo'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://[1::2]:3:4',
+    // pre-v6
+    'nodejs': 'http://:4/[1::2]:3',
+    'override': 'http://[1::2]:3:4/' // https://url.spec.whatwg.org/interop/test-results/73fe5361ec
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://2001::1',
+    // pre-v6
+    'nodejs': 'http://2001:1/:',
+    'override': 'http://2001::1' // https://url.spec.whatwg.org/interop/test-results/96db824e63
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://2001::1]',
+    // pre-v6 - nodejs is an outlier here
+    'nodejs': 'http://2001/::1]',
+    'override': 'http://2001::1]' // https://url.spec.whatwg.org/interop/test-results/85201c8d8f
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://2001::1]:80',
+    // pre-v6
+    'nodejs': 'http://2001:80/::1]',
+    'override': 'http://2001::1]:80' // https://url.spec.whatwg.org/interop/test-results/f921120f8c
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://[2001::1]',
+    'nodejs': 'http://[2001::1]/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http://[2001::1]:80',
+    // FIXME: This is failing WHATWG, should return http://[2001::1]/
+    // https://url.spec.whatwg.org/interop/test-results/2757692299
+    'nodejs': 'http://[2001::1]:80/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:/example.com/',
+    'nodejs': 'http://example.org/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ftp:/example.com/',
+    'nodejs': 'ftp://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'https:/example.com/',
+    'nodejs': 'https://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'madeupscheme:/example.com/',
+    'nodejs': 'madeupscheme:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'file:/example.com/',
+    'nodejs': 'file://example.com/',
+    'override': 'file:///example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ftps:/example.com/',
+    'nodejs': 'ftps:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'gopher:/example.com/',
+    'nodejs': 'gopher://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ws:/example.com/',
+    'nodejs': 'ws:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'wss:/example.com/',
+    'nodejs': 'wss:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'data:/example.com/',
+    'nodejs': 'data:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'javascript:/example.com/',
+    'nodejs': 'javascript:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'mailto:/example.com/',
+    'nodejs': 'mailto:/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'http:example.com/',
+    'nodejs': 'http://example.org/foo/example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ftp:example.com/',
+    'nodejs': 'ftp://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'https:example.com/',
+    'nodejs': 'https://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'madeupscheme:example.com/',
+    'nodejs': 'madeupscheme:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ftps:example.com/',
+    'nodejs': 'ftps:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'gopher:example.com/',
+    'nodejs': 'gopher://example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'ws:example.com/',
+    'nodejs': 'ws:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'wss:example.com/',
+    'nodejs': 'wss:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'data:example.com/',
+    'nodejs': 'data:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'javascript:example.com/',
+    'nodejs': 'javascript:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'mailto:example.com/',
+    'nodejs': 'mailto:example.com/'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/a/b/c',
+    'nodejs': 'http://example.org/a/b/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/a/ /c',
+    'nodejs': 'http://example.org/a/%20/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/a%2fc',
+    'nodejs': 'http://example.org/a%2fc'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '/a/%2f/c',
+    'nodejs': 'http://example.org/a/%2f/c'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': '#\u03b2',
+    'nodejs': 'http://example.org/foo/bar#\u03b2'
+  },
+  {
+    'base': 'http://example.org/foo/bar',
+    'input': 'data:text/html,test#test',
+    'nodejs': 'data:text/html,test#test'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file:c:\\foo\\bar.html',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/8c35076c8c
+    'refimpl': 'file:///C:/foo/bar',
+    'nodejs': 'file:///tmp/mock/c:/foo/bar.html'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '  File:c|////foo\\bar.html',
+    // pre-v6
+    'nodejs': 'file://c/%7C////foo/bar.html',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/4f239944e1
+    'refimpl': 'file:///C:/foo/bar',
+    'override': 'file:///tmp/mock/c%7C////foo/bar.html'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'C|/foo/bar',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/b1430fc379
+    'refimpl': 'file:///C:/foo/bar',
+    'nodejs': 'file:///tmp/mock/C%7C/foo/bar'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '/C|\\foo\\bar',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/4f239944e1
+    'refimpl': 'file:///C:/foo/bar',
+    'nodejs': 'file:///C%7C/foo/bar'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '//C|/foo/bar',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/9dc9a8fa31
+    'refimpl': 'file:///C:/foo/bar',
+    'nodejs': 'file://c/%7C/foo/bar'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '//server/file',
+    'nodejs': 'file://server/file'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '\\\\server\\file',
+    'nodejs': 'file://server/file'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '/\\server/file',
+    'nodejs': 'file://server/file'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file:///foo/bar.txt',
+    'nodejs': 'file:///foo/bar.txt'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file:///home/me',
+    'nodejs': 'file:///home/me'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '//',
+    'nodejs': 'file://',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/ebfaa37416
+    // Neither pre-v6 or v6 is correct
+    'refimpl': 'file:///',
+    'override': 'file:////'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '///',
+    'nodejs': 'file:///'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': '///test',
+    'nodejs': 'file:///test'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file://test',
+    'nodejs': 'file://test/'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file://localhost',
+    'nodejs': 'file://localhost/'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file://localhost/',
+    'nodejs': 'file://localhost/'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file://localhost/test',
+    'nodejs': 'file://localhost/test'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'test',
+    'nodejs': 'file:///tmp/mock/test'
+  },
+  {
+    'base': 'file:///tmp/mock/path',
+    'input': 'file:test',
+    'nodejs': 'file:///tmp/mock/test'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/././foo',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/22f485f543
+    'refimpl': 'http://example.com/foo',
+    'nodejs': 'http://example.com/././foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/./.foo',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/e1d6c4e019
+    'refimpl': 'http://example.com/.foo',
+    'nodejs': 'http://example.com/./.foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/.',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/e1d6c4e019
+    'refimpl': 'http://example.com/foo/',
+    'nodejs': 'http://example.com/foo/.'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/./',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/b48b8bb38e
+    'refimpl': 'http://example.com/foo/',
+    'nodejs': 'http://example.com/foo/./'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar/..',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/1b005cdfe9
+    'refimpl': 'http://example.com/foo/',
+    'nodejs': 'http://example.com/foo/bar/..'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar/../',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/8fc653ea6b
+    'refimpl': 'http://example.com/foo/',
+    'nodejs': 'http://example.com/foo/bar/../'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/..bar',
+    'nodejs': 'http://example.com/foo/..bar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar/../ton',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/e27195ad3c
+    'refimpl': 'http://example.com/foo/ton',
+    'nodejs': 'http://example.com/foo/bar/../ton'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar/../ton/../../a',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/84a25b8dc7
+    'refimpl': 'http://example.com/a',
+    'nodejs': 'http://example.com/foo/bar/../ton/../../a'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/../../..',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/863dbcb8b6
+    'refimpl': 'http://example.com/',
+    'nodejs': 'http://example.com/foo/../../..'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/../../../ton',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/a01656d820
+    'refimpl': 'http://example.com/ton',
+    'nodejs': 'http://example.com/foo/../../../ton'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/%2e',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/a78e460b47
+    'refimpl': 'http://example.com/',
+    'nodejs': 'http://example.com/foo/%2e'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/%2e%2',
+    'nodejs': 'http://example.com/foo/%2e%2'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/%2e./%2e%2e/.%2e/%2e.bar',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/27c205abd8
+    'refimpl': 'http://example.com/%2e.bar',
+    'nodejs': 'http://example.com/foo/%2e./%2e%2e/.%2e/%2e.bar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com////../..',
+    // FIXME: This is failing WHATWG
+    // https://url.spec.whatwg.org/interop/test-results/e1ed8b8d91
+    'refimpl': 'http://example.com//',
+    'nodejs': 'http://example.com////../..'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar//../..',
+    'nodejs': 'http://example.com/foo/bar//../..'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo/bar//..',
+    'nodejs': 'http://example.com/foo/bar//..'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo',
+    'nodejs': 'http://example.com/foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/%20foo',
+    'nodejs': 'http://example.com/%20foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%',
+    'nodejs': 'http://example.com/foo%'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%2',
+    'nodejs': 'http://example.com/foo%2'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%2zbar',
+    'nodejs': 'http://example.com/foo%2zbar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%2\u00c2\u00a9zbar',
+    'nodejs': 'http://example.com/foo%2\u00c2\u00a9zbar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%41%7a',
+    'nodejs': 'http://example.com/foo%41%7a'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo\t\u0091%91',
+    'nodejs': 'http://example.com/foo%09\u0091%91'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo%00%51',
+    'nodejs': 'http://example.com/foo%00%51'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/(%28:%3A%29)',
+    'nodejs': 'http://example.com/(%28:%3A%29)'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/%3A%3a%3C%3c',
+    'nodejs': 'http://example.com/%3A%3a%3C%3c'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/foo\tbar',
+    'nodejs': 'http://example.com/foo%09bar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com\\\\foo\\\\bar',
+    'nodejs': 'http://example.com//foo//bar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/%7Ffp3%3Eju%3Dduvgw%3Dd',
+    'nodejs': 'http://example.com/%7Ffp3%3Eju%3Dduvgw%3Dd'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/@asdf%40',
+    'nodejs': 'http://example.com/@asdf%40'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/\u4f60\u597d\u4f60\u597d',
+    'nodejs': 'http://example.com/\u4f60\u597d\u4f60\u597d'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/\u2025/foo',
+    'nodejs': 'http://example.com/\u2025/foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/\ufeff/foo',
+    'nodejs': 'http://example.com/\ufeff/foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://example.com/\u202e/foo/\u202d/bar',
+    'nodejs': 'http://example.com/\u202e/foo/\u202d/bar'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www.google.com/foo?bar=baz#',
+    'nodejs': 'http://www.google.com/foo?bar=baz#'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www.google.com/foo?bar=baz# \u00bb',
+    'nodejs': 'http://www.google.com/foo?bar=baz#%20\u00bb'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'data:test# \u00bb',
+    'nodejs': 'data:test#%20\u00bb'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://[www.google.com]/',
+    'nodejs': 'http://[www.google.com]/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www.google.com',
+    'nodejs': 'http://www.google.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://192.0x00A80001',
+    'nodejs': 'http://192.0x00a80001/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www/foo%2Ehtml',
+    'nodejs': 'http://www/foo%2Ehtml'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www/foo/%2E/html',
+    'nodejs': 'http://www/foo/%2E/html'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://user:pass@/',
+    'nodejs': 'http:///'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://%25DOMAIN:foobar@foodomain.com/',
+    'nodejs': 'http://%25DOMAIN:foobar@foodomain.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:\\\\www.google.com\\foo',
+    'nodejs': 'http://www.google.com/foo'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://foo:80/',
+    'nodejs': 'http://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://foo:81/',
+    'nodejs': 'http://foo:81/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'httpa://foo:80/',
+    'nodejs': 'httpa://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://foo:-80/',
+    'nodejs': 'http://foo/:-80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'https://foo:443/',
+    'nodejs': 'https://foo:443/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'https://foo:80/',
+    'nodejs': 'https://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftp://foo:21/',
+    'nodejs': 'ftp://foo:21/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftp://foo:80/',
+    'nodejs': 'ftp://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'gopher://foo:70/',
+    'nodejs': 'gopher://foo:70/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'gopher://foo:443/',
+    'nodejs': 'gopher://foo:443/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws://foo:80/',
+    'nodejs': 'ws://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws://foo:81/',
+    'nodejs': 'ws://foo:81/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws://foo:443/',
+    'nodejs': 'ws://foo:443/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws://foo:815/',
+    'nodejs': 'ws://foo:815/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss://foo:80/',
+    'nodejs': 'wss://foo:80/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss://foo:81/',
+    'nodejs': 'wss://foo:81/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss://foo:443/',
+    'nodejs': 'wss://foo:443/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss://foo:815/',
+    'nodejs': 'wss://foo:815/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/example.com/',
+    'nodejs': 'http://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftp:/example.com/',
+    'nodejs': 'ftp://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'https:/example.com/',
+    'nodejs': 'https://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'madeupscheme:/example.com/',
+    'nodejs': 'madeupscheme:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'file:/example.com/',
+    'nodejs': 'file://example.com/',
+    'override': 'file:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftps:/example.com/',
+    'nodejs': 'ftps:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'gopher:/example.com/',
+    'nodejs': 'gopher://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws:/example.com/',
+    'nodejs': 'ws:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss:/example.com/',
+    'nodejs': 'wss:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'data:/example.com/',
+    'nodejs': 'data:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'javascript:/example.com/',
+    'nodejs': 'javascript:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'mailto:/example.com/',
+    'nodejs': 'mailto:/example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:example.com/',
+    'nodejs': 'http://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftp:example.com/',
+    'nodejs': 'ftp://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'https:example.com/',
+    'nodejs': 'https://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'madeupscheme:example.com/',
+    'nodejs': 'madeupscheme:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ftps:example.com/',
+    'nodejs': 'ftps:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'gopher:example.com/',
+    'nodejs': 'gopher://example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'ws:example.com/',
+    'nodejs': 'ws:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'wss:example.com/',
+    'nodejs': 'wss:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'data:example.com/',
+    'nodejs': 'data:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'javascript:example.com/',
+    'nodejs': 'javascript:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'mailto:example.com/',
+    'nodejs': 'mailto:example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:@www.example.com',
+    'nodejs': 'http://@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/@www.example.com',
+    'nodejs': 'http://@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://@www.example.com',
+    'nodejs': 'http://www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:a:b@www.example.com',
+    'nodejs': 'http://a:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/a:b@www.example.com',
+    'nodejs': 'http://a:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://a:b@www.example.com',
+    'nodejs': 'http://a:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://@pple.com',
+    'nodejs': 'http://pple.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http::b@www.example.com',
+    'nodejs': 'http://:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/:b@www.example.com',
+    'nodejs': 'http://:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://:b@www.example.com',
+    'nodejs': 'http://:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/:@/www.example.com',
+    'nodejs': 'http://:@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://user@/www.example.com',
+    'nodejs': 'http://user@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:@/www.example.com',
+    'nodejs': 'http://@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/@/www.example.com',
+    'nodejs': 'http://@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://@/www.example.com',
+    'nodejs': 'http://www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'https:@/www.example.com',
+    'nodejs': 'https://@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:a:b@/www.example.com',
+    'nodejs': 'http://a:b@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/a:b@/www.example.com',
+    'nodejs': 'http://a:b@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://a:b@/www.example.com',
+    'nodejs': 'http://a:b@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http::@/www.example.com',
+    'nodejs': 'http://:@/www.example.com'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:a:@www.example.com',
+    'nodejs': 'http://a:@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/a:@www.example.com',
+    'nodejs': 'http://a:@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://a:@www.example.com',
+    'nodejs': 'http://a:@www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://www.@pple.com',
+    'nodejs': 'http://www.@pple.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:@:www.example.com',
+    'nodejs': 'http://@:www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http:/@:www.example.com',
+    'nodejs': 'http://@:www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://@:www.example.com',
+    'nodejs': 'http://:www.example.com/'
+  },
+  {
+    'base': 'about:blank',
+    'input': 'http://:@www.example.com',
+    'nodejs': 'http://:@www.example.com/'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '/',
+    'nodejs': 'http://www.example.com/'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '/test.txt',
+    'nodejs': 'http://www.example.com/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '.',
+    'nodejs': 'http://www.example.com/'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '..',
+    'nodejs': 'http://www.example.com/'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': 'test.txt',
+    'nodejs': 'http://www.example.com/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': './test.txt',
+    'nodejs': 'http://www.example.com/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '../test.txt',
+    'nodejs': 'http://www.example.com/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '../aaa/test.txt',
+    'nodejs': 'http://www.example.com/aaa/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '../../test.txt',
+    'nodejs': 'http://www.example.com/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '\u4e2d/test.txt',
+    'nodejs': 'http://www.example.com/\u4e2d/test.txt'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': 'http://www.example2.com',
+    'nodejs': 'http://www.example2.com/'
+  },
+  {
+    'base': 'http://www.example.com/test',
+    'input': '//www.example2.com',
+    'nodejs': 'http://www.example2.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://ExAmPlE.CoM',
+    'nodejs': 'http://example.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://example example.com',
+    'nodejs': 'http://example/%20example.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://Goo%20 goo%7C|.com',
+    'nodejs': 'http://goo/%20%20goo%7C%7C.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://GOO\u00a0\u3000goo.com',
+    'nodejs': 'http://xn--googoo-rga8318g.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://GOO\u200b\u2060\ufeffgoo.com',
+    'nodejs': 'http://xn--googoo-df0c40ax241n.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://www.foo\u3002bar.com',
+    'nodejs': 'http://www.foo.bar.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\ufdd0zyx.com',
+    'nodejs': 'http://xn--zyx-h05s.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%ef%b7%90zyx.com',
+    'nodejs': 'http://other.com/%ef%b7%90zyx.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\uff27\uff4f.com',
+    'nodejs': 'http://xn--si7cqa.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\uff05\uff14\uff11.com',
+    'nodejs': 'http://xn--wg7cyai.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%ef%bc%85%ef%bc%94%ef%bc%91.com',
+    'nodejs': 'http://other.com/%ef%bc%85%ef%bc%94%ef%bc%91.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\uff05\uff10\uff10.com',
+    'nodejs': 'http://xn--wg7cwaa.com/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%ef%bc%85%ef%bc%90%ef%bc%90.com',
+    'nodejs': 'http://other.com/%ef%bc%85%ef%bc%90%ef%bc%90.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\u4f60\u597d\u4f60\u597d',
+    'nodejs': 'http://xn--6qqa088eba/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%zz%66%a.com',
+    'nodejs': 'http://other.com/%zz%66%a.com'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%25',
+    'nodejs': 'http://other.com/%25'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://hello%00',
+    'nodejs': 'http://hello/%00'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%30%78%63%30%2e%30%32%35%30.01',
+    'nodejs': 'http://other.com/%30%78%63%30%2e%30%32%35%30.01'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%30%78%63%30%2e%30%32%35%30.01%2e',
+    'nodejs': 'http://other.com/%30%78%63%30%2e%30%32%35%30.01%2e'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://192.168.0.257',
+    'nodejs': 'http://192.168.0.257/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://%3g%78%63%30%2e%30%32%35%30%2E.01',
+    'nodejs': 'http://other.com/%3g%78%63%30%2e%30%32%35%30%2E.01'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://192.168.0.1 hello',
+    'nodejs': 'http://192.168.0.1/%20hello'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://\uff10\uff38\uff43\uff10\uff0e\uff10\uff12\uff15\uff10\uff0e\uff10\uff11',
+    'nodejs': 'http://xn--7g7ca6m5c.xn--7g7cafm.xn--7g7cc/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://[google.com]',
+    'nodejs': 'http://[google.com]/'
+  },
+  {
+    'base': 'http://other.com/',
+    'input': 'http://foo:\ud83d\udca9@example.com/bar',
+    'nodejs': 'http://foo:%F0%9F%92%A9@example.com/bar'
+  },
+  {
+    'base': 'test:test',
+    'input': 'x',
+    'nodejs': 'test:x'
+  }
+];
+
+whatwgTests.forEach(function(test) {
+  var expected = test.override !== undefined ? test.override : test.nodejs;
+  assert.equal(url.resolve(test.base, test.input), expected);
+});