LibWeb: Add fieldset elements property

Author: https://github.com/bplaat
Commit: https://github.com/SerenityOS/serenity/commit/ea04a86715
Pull-request: https://github.com/SerenityOS/serenity/pull/22235

Tests/LibWeb/Text/expected/fieldset-elements.txt

@@ -0,0 +1,2 @@
+1. 3
+2. "PASS"

Tests/LibWeb/Text/input/fieldset-elements.html

@@ -0,0 +1,24 @@
+<script src="./include.js"></script>
+<script>
+    test(() => {
+        let testCounter = 1;
+        function testPart(part) {
+            println(`${testCounter++}. ${JSON.stringify(part())}`);
+        }
+
+        // 1. Get fieldset elements length
+        testPart(() => {
+            const fieldset = document.createElement('fieldset');
+            fieldset.innerHTML = `<input><input><button></button>`;
+            return fieldset.elements.length;
+        });
+
+        // 2. Get fieldset elements set stuff
+        testPart(() => {
+            const fieldset = document.createElement('fieldset');
+            fieldset.innerHTML = `<input><input value="FAIL"><button></button>`;
+            fieldset.elements[0].value = 'PASS';
+            return fieldset.children[0].value;
+        });
+    });
+</script>

Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.cpp

@@ -5,8 +5,14 @@
  */
 
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/HTML/HTMLButtonElement.h>
 #include <LibWeb/HTML/HTMLFieldSetElement.h>
+#include <LibWeb/HTML/HTMLInputElement.h>
 #include <LibWeb/HTML/HTMLLegendElement.h>
+#include <LibWeb/HTML/HTMLObjectElement.h>
+#include <LibWeb/HTML/HTMLOutputElement.h>
+#include <LibWeb/HTML/HTMLSelectElement.h>
+#include <LibWeb/HTML/HTMLTextAreaElement.h>
 
 namespace Web::HTML {
 
@@ -25,6 +31,12 @@ void HTMLFieldSetElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLFieldSetElementPrototype>(realm, "HTMLFieldSetElement"_fly_string));
 }
 
+void HTMLFieldSetElement::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_elements);
+}
+
 // https://html.spec.whatwg.org/multipage/form-elements.html#concept-fieldset-disabled
 bool HTMLFieldSetElement::is_disabled() const
 {
@@ -45,4 +57,23 @@ bool HTMLFieldSetElement::is_disabled() const
     return false;
 }
 
+// https://html.spec.whatwg.org/multipage/form-elements.html#dom-fieldset-elements
+JS::GCPtr<DOM::HTMLCollection> const& HTMLFieldSetElement::elements()
+{
+    // The elements IDL attribute must return an HTMLCollection rooted at the fieldset element, whose filter matches listed elements.
+    if (!m_elements) {
+        m_elements = DOM::HTMLCollection::create(*this, DOM::HTMLCollection::Scope::Descendants, [](DOM::Element const& element) {
+            // FIXME: Form-associated custom elements return also true
+            return is<HTMLButtonElement>(element)
+                || is<HTMLFieldSetElement>(element)
+                || is<HTMLInputElement>(element)
+                || is<HTMLObjectElement>(element)
+                || is<HTMLOutputElement>(element)
+                || is<HTMLSelectElement>(element)
+                || is<HTMLTextAreaElement>(element);
+        });
+    }
+    return m_elements;
+}
+
 }

Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <LibWeb/ARIA/Roles.h>
+#include <LibWeb/DOM/HTMLCollection.h>
 #include <LibWeb/HTML/FormAssociatedElement.h>
 #include <LibWeb/HTML/HTMLElement.h>
 
@@ -30,6 +31,8 @@ public:
 
     bool is_disabled() const;
 
+    JS::GCPtr<DOM::HTMLCollection> const& elements();
+
     // ^FormAssociatedElement
     // https://html.spec.whatwg.org/multipage/forms.html#category-listed
     virtual bool is_listed() const override { return true; }
@@ -43,6 +46,9 @@ private:
     HTMLFieldSetElement(DOM::Document&, DOM::QualifiedName);
 
     virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    JS::GCPtr<DOM::HTMLCollection> m_elements;
 };
 
 }

Userland/Libraries/LibWeb/HTML/HTMLFieldSetElement.idl

@@ -12,7 +12,7 @@ interface HTMLFieldSetElement : HTMLElement {
 
     readonly attribute DOMString type;
 
-    // FIXME: [SameObject] readonly attribute HTMLCollection elements;
+    [SameObject] readonly attribute HTMLCollection elements;
 
     // FIXME: readonly attribute boolean willValidate;
     // FIXME: [SameObject] readonly attribute ValidityState validity;

Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp

@@ -396,6 +396,8 @@ static bool is_form_control(DOM::Element const& element)
         return true;
     }
 
+    // FIXME: Form-associated custom elements return also true
+
     return false;
 }