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>

1 files changed, 10 insertions, 7 deletions

diff --git a/lib/url.js b/lib/url.js
index e4ced8e860..2b7dd6e532 100644
--- a/lib/url.js
+++ b/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);
-
-  else if (typeof obj !== 'object' || obj === null)
+  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)) {
+    var format = obj[internalUrl.formatSymbol];
+    return format ?
+      format.call(obj, options) :
+      Url.prototype.format.call(obj);
+  }
   return obj.format();
 }