LibWeb: Implement HTMLSelectElement.selectedIndex

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/a606345576

Userland/Libraries/LibWeb/HTML/HTMLOptionElement.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -16,6 +17,13 @@ public:
 
     HTMLOptionElement(DOM::Document&, DOM::QualifiedName);
     virtual ~HTMLOptionElement() override;
+
+private:
+    // https://html.spec.whatwg.org/multipage/form-elements.html#concept-option-selectedness
+    bool m_selected { false };
+
+    // https://html.spec.whatwg.org/multipage/form-elements.html#concept-option-dirtiness
+    bool m_dirty { false };
 };
 
 }

Userland/Libraries/LibWeb/HTML/HTMLSelectElement.cpp

@@ -1,11 +1,12 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibWeb/HTML/HTMLFormElement.h>
+#include <LibWeb/HTML/HTMLOptGroupElement.h>
 #include <LibWeb/HTML/HTMLOptionElement.h>
 #include <LibWeb/HTML/HTMLSelectElement.h>
 
@@ -33,4 +34,56 @@ RefPtr<HTMLOptionsCollection> const& HTMLSelectElement::options()
     return m_options;
 }
 
+// https://html.spec.whatwg.org/multipage/form-elements.html#concept-select-option-list
+NonnullRefPtrVector<HTMLOptionElement> HTMLSelectElement::list_of_options() const
+{
+    // The list of options for a select element consists of all the option element children of the select element,
+    // and all the option element children of all the optgroup element children of the select element, in tree order.
+    NonnullRefPtrVector<HTMLOptionElement> list;
+
+    for_each_child_of_type<HTMLOptionElement>([&](HTMLOptionElement const& option_element) {
+        list.append(option_element);
+    });
+
+    for_each_child_of_type<HTMLOptGroupElement>([&](HTMLOptGroupElement const& optgroup_element) {
+        optgroup_element.for_each_child_of_type<HTMLOptionElement>([&](HTMLOptionElement const& option_element) {
+            list.append(option_element);
+        });
+    });
+
+    return list;
+}
+
+// https://html.spec.whatwg.org/multipage/form-elements.html#dom-select-selectedindex
+int HTMLSelectElement::selected_index() const
+{
+    // The selectedIndex IDL attribute, on getting, must return the index of the first option element in the list of options
+    // in tree order that has its selectedness set to true, if any. If there isn't one, then it must return −1.
+
+    int index = 0;
+    for (auto const& option_element : list_of_options()) {
+        if (option_element.selected())
+            return index;
+        ++index;
+    }
+    return -1;
+}
+
+void HTMLSelectElement::set_selected_index(int index)
+{
+    // On setting, the selectedIndex attribute must set the selectedness of all the option elements in the list of options to false,
+    // and then the option element in the list of options whose index is the given new value,
+    // if any, must have its selectedness set to true and its dirtiness set to true.
+    auto options = list_of_options();
+    for (auto& option : options)
+        option.m_selected = false;
+
+    if (index < 0 || index >= static_cast<int>(options.size()))
+        return;
+
+    auto& selected_option = options[index];
+    selected_option.m_selected = true;
+    selected_option.m_dirty = true;
+}
+
 }

Userland/Libraries/LibWeb/HTML/HTMLSelectElement.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2022, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, Luke Wilde <lukew@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -23,6 +23,11 @@ public:
 
     RefPtr<HTMLOptionsCollection> const& options();
 
+    int selected_index() const;
+    void set_selected_index(int);
+
+    NonnullRefPtrVector<HTMLOptionElement> list_of_options() const;
+
     // ^FormAssociatedElement
     // https://html.spec.whatwg.org/multipage/forms.html#category-listed
     virtual bool is_listed() const override { return true; }

Userland/Libraries/LibWeb/HTML/HTMLSelectElement.idl

@@ -8,4 +8,6 @@ interface HTMLSelectElement : HTMLElement {
     [Reflect] attribute boolean required;
     [SameObject] readonly attribute HTMLOptionsCollection options;
 
+    attribute long selectedIndex;
+
 };