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, 102 insertions, 0 deletions

diff --git a/test/parallel/test-url-format-whatwg.js b/test/parallel/test-url-format-whatwg.js
new file mode 100644
index 0000000000..507d3f8419
--- /dev/null
+++ b/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'
+);