Fix passing empty fragmentIdentifier to stringifyUrl()

Fixes #380

Author: sindresorhus

base.js

@@ -489,7 +489,7 @@ export function stringifyUrl(object, options) {
 	}
 
 	let hash = getHash(object.url);
-	if (object.fragmentIdentifier) {
+	if (typeof object.fragmentIdentifier === 'string') {
 		const urlObjectForFragmentEncode = new URL(url);
 		urlObjectForFragmentEncode.hash = object.fragmentIdentifier;
 		hash = options[encodeFragmentIdentifier] ? urlObjectForFragmentEncode.hash : `#${object.fragmentIdentifier}`;

test/stringify-url.js

@@ -27,6 +27,7 @@ test('stringify URL with fragment identifier', t => {
 	t.is(queryString.stringifyUrl({url: 'https://foo.bar', query: {}}), 'https://foo.bar');
 	t.is(queryString.stringifyUrl({url: 'https://foo.bar', query: {}, fragmentIdentifier: 'foo bar'}), 'https://foo.bar#foo%20bar');
 	t.is(queryString.stringifyUrl({url: 'https://foo.bar/', query: {}, fragmentIdentifier: '/foo/bar'}), 'https://foo.bar/#/foo/bar');
+	t.is(queryString.stringifyUrl({url: 'https://foo.bar/#foo', query: {}, fragmentIdentifier: ''}), 'https://foo.bar/');
 });
 
 test('skipEmptyString:: stringify URL with a query string', t => {