url: fix URLSearchParams(null) to prudce null= per spec

Signed-off-by: marcopiraccini <marco.piraccini@gmail.com>
PR-URL: #63782Fixes: #63559
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: marcopiraccini

lib/internal/url.js

@@ -337,9 +337,9 @@ class URLSearchParams {
 constructor(init=undefined){
 markTransferMode(this,false,false);
 
-if(init==null){
+if(init===undefined){
 // Do nothing
-}elseif(typeofinit==='object'||typeofinit==='function'){
+}elseif(init!==null&&(typeofinit==='object'||typeofinit==='function')){
 constmethod=init[SymbolIterator];
 if(method===this[SymbolIterator]&& #searchParams ininit){
 // While the spec does not have this branch, we can use it as a

test/parallel/test-whatwg-url-custom-searchparams-constructor.js

@@ -28,8 +28,14 @@ function makeIterableFunc(array) {
 letparams;
 params=newURLSearchParams(undefined);
 assert.strictEqual(params.toString(),'');
+// Per WebIDL union resolution, null is coerced to the USVString "null".
+// Refs: https://url.spec.whatwg.org/#interface-urlsearchparams
 params=newURLSearchParams(null);
-assert.strictEqual(params.toString(),'');
+assert.strictEqual(params.toString(),'null=');
+params=newURLSearchParams(false);
+assert.strictEqual(params.toString(),'false=');
+params=newURLSearchParams(0);
+assert.strictEqual(params.toString(),'0=');
 params=newURLSearchParams(
 makeIterableFunc([['key','val'],['key2','val2']])
 );