url: extend url.format to support WHATWG URL

Removes the non-standard options on WHATWG URL toString
and extends the existing url.format() API to support
customizable serialization of the WHATWG URL object.

This does not yet include the documentation updates
because the documentation for the new WHATWG URL object
has not yet landed.

Example:

```js
const url = require('url');
const URL = url.URL;
const myURL = new URL('http://example.org/?a=b#c');
const str = url.format(myURL, {fragment: false, search: false});
console.log(str);
  // Prints: http://example.org/
```

PR-URL: https://github.com/nodejs/node/pull/10857
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

lib/internal/url.js

@@ -1,13 +1,5 @@
 'use strict';
 
-function getPunycode() {
-  try {
-    return process.binding('icu');
-  } catch (err) {
-    return require('punycode');
-  }
-}
-const punycode = getPunycode();
 const util = require('util');
 const binding = process.binding('url');
 const context = Symbol('context');
@@ -20,6 +12,7 @@ const kScheme = Symbol('scheme');
 const kHost = Symbol('host');
 const kPort = Symbol('port');
 const kDomain = Symbol('domain');
+const kFormat = Symbol('format');
 
 // https://tc39.github.io/ecma262/#sec-%iteratorprototype%-object
 const IteratorPrototype = Object.getPrototypeOf(
@@ -263,18 +256,19 @@ class URL {
 }
 
 Object.defineProperties(URL.prototype, {
-  toString: {
+  [kFormat]: {
-    // https://heycam.github.io/webidl/#es-stringifier
+    enumerable: false,
-    writable: true,
+    configurable: false,
-    enumerable: true,
-    configurable: true,
     // eslint-disable-next-line func-name-matching
-    value: function toString(options) {
+    value: function format(options) {
-      options = options || {};
+      if (options && typeof options !== 'object')
-      const fragment =
+        throw new TypeError('options must be an object');
-        options.fragment !== undefined ?
+      options = Object.assign({
-          !!options.fragment : true;
+        fragment: true,
-      const unicode = !!options.unicode;
+        unicode: false,
+        search: true,
+        auth: true
+      }, options);
       const ctx = this[context];
       var ret;
       if (this.protocol)
@@ -284,28 +278,23 @@ Object.defineProperties(URL.prototype, {
         const has_username = typeof ctx.username === 'string';
         const has_password = typeof ctx.password === 'string' &&
                              ctx.password !== '';
-        if (has_username || has_password) {
+        if (options.auth && (has_username || has_password)) {
           if (has_username)
             ret += ctx.username;
           if (has_password)
             ret += `:${ctx.password}`;
           ret += '@';
         }
-        if (unicode) {
+        ret += options.unicode ?
-          ret += punycode.toUnicode(this.hostname);
+          domainToUnicode(this.host) : this.host;
-          if (this.port !== undefined)
-            ret += `:${this.port}`;
-        } else {
-          ret += this.host;
-        }
       } else if (ctx.scheme === 'file:') {
         ret += '//';
       }
       if (this.pathname)
         ret += this.pathname;
-      if (typeof ctx.query === 'string')
+      if (options.search && typeof ctx.query === 'string')
         ret += `?${ctx.query}`;
-      if (fragment & typeof ctx.fragment === 'string')
+      if (options.fragment && typeof ctx.fragment === 'string')
         ret += `#${ctx.fragment}`;
       return ret;
     }
@@ -314,11 +303,21 @@ Object.defineProperties(URL.prototype, {
     configurable: true,
     value: 'URL'
   },
+  toString: {
+    // https://heycam.github.io/webidl/#es-stringifier
+    writable: true,
+    enumerable: true,
+    configurable: true,
+    // eslint-disable-next-line func-name-matching
+    value: function toString() {
+      return this[kFormat]({});
+    }
+  },
   href: {
     enumerable: true,
     configurable: true,
     get() {
-      return this.toString();
+      return this[kFormat]({});
     },
     set(input) {
       parse(this, input);
@@ -1120,3 +1119,4 @@ exports.domainToASCII = domainToASCII;
 exports.domainToUnicode = domainToUnicode;
 exports.encodeAuth = encodeAuth;
 exports.urlToOptions = urlToOptions;
+exports.formatSymbol = kFormat;

lib/url.js

@@ -538,19 +538,22 @@ function autoEscapeStr(rest) {
 }
 
 // format a parsed object into a url string
-function urlFormat(obj) {
+function urlFormat(obj, options) {
   // 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);
+  if (typeof obj === 'string') {
-
+    obj = urlParse(obj);
-  else if (typeof obj !== 'object' || obj === null)
+  } 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)) {
-  else if (!(obj instanceof Url)) return Url.prototype.format.call(obj);
+    var format = obj[internalUrl.formatSymbol];
-
+    return format ?
+      format.call(obj, options) :
+      Url.prototype.format.call(obj);
+  }
   return obj.format();
 }
 

test/parallel/test-url-format-whatwg.js

@@ -0,0 +1,102 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const url = require('url');
+const URL = url.URL;
+
+const myURL = new URL('http://xn--lck1c3crb1723bpq4a.com/a?a=b#c');
+
+assert.strictEqual(
+  url.format(myURL),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+const errreg = /^TypeError: options must be an object$/;
+assert.throws(() => url.format(myURL, true), errreg);
+assert.throws(() => url.format(myURL, 1), errreg);
+assert.throws(() => url.format(myURL, 'test'), errreg);
+assert.throws(() => url.format(myURL, Infinity), errreg);
+
+// Any falsy value other than undefined will be treated as false.
+// Any truthy value will be treated as true.
+
+assert.strictEqual(
+  url.format(myURL, {fragment: false}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b'
+);
+
+assert.strictEqual(
+  url.format(myURL, {fragment: ''}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b'
+);
+
+assert.strictEqual(
+  url.format(myURL, {fragment: 0}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b'
+);
+
+assert.strictEqual(
+  url.format(myURL, {fragment: 1}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {fragment: {}}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {search: false}),
+  'http://xn--lck1c3crb1723bpq4a.com/a#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {search: ''}),
+  'http://xn--lck1c3crb1723bpq4a.com/a#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {search: 0}),
+  'http://xn--lck1c3crb1723bpq4a.com/a#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {search: 1}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {search: {}}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {unicode: true}),
+  'http://理容ナカムラ.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {unicode: 1}),
+  'http://理容ナカムラ.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {unicode: {}}),
+  'http://理容ナカムラ.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {unicode: false}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);
+
+assert.strictEqual(
+  url.format(myURL, {unicode: 0}),
+  'http://xn--lck1c3crb1723bpq4a.com/a?a=b#c'
+);