url: fix lint and deopt issues

The deopt issues arose from the use of const in specific situations
that v8 does not fully support yet.

Fixes: https://github.com/nodejs/node/issues/5299
PR-URL: https://github.com/nodejs/node/pull/5300
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

lib/url.js

@@ -81,17 +81,18 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
   var end = -1;
   var rest = '';
   var lastPos = 0;
-  for (var i = 0, inWs = false, split = false; i < url.length; ++i) {
-    var code = url.charCodeAt(i);
+  var i = 0;
+  for (var inWs = false, split = false; i < url.length; ++i) {
+    const code = url.charCodeAt(i);
 
     // Find first and last non-whitespace characters for trimming
-    var isWs = code === 32/* */ ||
-               code === 9/*\t*/ ||
-               code === 13/*\r*/ ||
-               code === 10/*\n*/ ||
-               code === 12/*\f*/ ||
-               code === 160/*\u00A0*/ ||
-               code === 65279/*\uFEFF*/;
+    const isWs = code === 32/* */ ||
+                 code === 9/*\t*/ ||
+                 code === 13/*\r*/ ||
+                 code === 10/*\n*/ ||
+                 code === 12/*\f*/ ||
+                 code === 160/*\u00A0*/ ||
+                 code === 65279/*\uFEFF*/;
     if (start === -1) {
       if (isWs)
         continue;
@@ -153,7 +154,7 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
 
   if (!slashesDenoteHost && !hasHash) {
     // Try fast path regexp
-    var simplePath = simplePathPattern.exec(rest);
+    const simplePath = simplePathPattern.exec(rest);
     if (simplePath) {
       this.path = rest;
       this.href = rest;
@@ -215,7 +216,7 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
     var hostEnd = -1;
     var atSign = -1;
     var nonHost = -1;
-    for (var i = 0; i < rest.length; ++i) {
+    for (i = 0; i < rest.length; ++i) {
       switch (rest.charCodeAt(i)) {
         case 9:   // '\t'
         case 10:  // '\n'
@@ -255,7 +256,7 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
       if (hostEnd !== -1)
         break;
     }
-    var start = 0;
+    start = 0;
     if (atSign !== -1) {
       this.auth = decodeURIComponent(rest.slice(0, atSign));
       start = atSign + 1;
@@ -284,9 +285,8 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
                        hostname.charCodeAt(hostname.length - 1) === 93/*]*/;
 
     // validate a little.
-    var result;
     if (!ipv6Hostname) {
-      result = validateHostname(this, rest, hostname);
+      const result = validateHostname(this, rest, hostname);
       if (result !== undefined)
         rest = result;
     }
@@ -326,15 +326,15 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
     // First, make 100% sure that any "autoEscape" chars get
     // escaped, even if encodeURIComponent doesn't think they
     // need to be.
-    result = autoEscapeStr(rest);
+    const result = autoEscapeStr(rest);
     if (result !== undefined)
       rest = result;
   }
 
   var questionIdx = -1;
   var hashIdx = -1;
-  for (var i = 0; i < rest.length; ++i) {
-    var code = rest.charCodeAt(i);
+  for (i = 0; i < rest.length; ++i) {
+    const code = rest.charCodeAt(i);
     if (code === 35/*#*/) {
       this.hash = rest.slice(i);
       hashIdx = i;
@@ -378,8 +378,8 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
 
   // to support http.request
   if (this.pathname || this.search) {
-    var p = this.pathname || '';
-    var s = this.search || '';
+    const p = this.pathname || '';
+    const s = this.search || '';
     this.path = p + s;
   }
 
@@ -720,17 +720,17 @@ Url.prototype.resolveObject = function(relative) {
     return result;
   }
 
-  const isSourceAbs = (result.pathname && result.pathname.charAt(0) === '/');
-  const isRelAbs = (
+  var isSourceAbs = (result.pathname && result.pathname.charAt(0) === '/');
+  var isRelAbs = (
       relative.host ||
       relative.pathname && relative.pathname.charAt(0) === '/'
   );
   var mustEndAbs = (isRelAbs || isSourceAbs ||
                     (result.host && relative.pathname));
-  const removeAllDots = mustEndAbs;
+  var removeAllDots = mustEndAbs;
   var srcPath = result.pathname && result.pathname.split('/') || [];
-  const relPath = relative.pathname && relative.pathname.split('/') || [];
-  const psychotic = result.protocol && !slashedProtocol[result.protocol];
+  var relPath = relative.pathname && relative.pathname.split('/') || [];
+  var psychotic = result.protocol && !slashedProtocol[result.protocol];
 
   // if the url is a non-slashed url, then relative
   // links like ../.. should be able