LibJS: Add the WeakMap built-in object

Userland/Libraries/LibJS/Runtime/WeakMapConstructor.cpp

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Error.h>
+#include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/IteratorOperations.h>
+#include <LibJS/Runtime/WeakMap.h>
+#include <LibJS/Runtime/WeakMapConstructor.h>
+
+namespace JS {
+
+WeakMapConstructor::WeakMapConstructor(GlobalObject& global_object)
+    : NativeFunction(vm().names.WeakMap, *global_object.function_prototype())
+{
+}
+
+void WeakMapConstructor::initialize(GlobalObject& global_object)
+{
+    auto& vm = this->vm();
+    NativeFunction::initialize(global_object);
+    define_property(vm.names.prototype, global_object.weak_map_prototype(), 0);
+    define_property(vm.names.length, Value(0), Attribute::Configurable);
+}
+
+WeakMapConstructor::~WeakMapConstructor()
+{
+}
+
+Value WeakMapConstructor::call()
+{
+    auto& vm = this->vm();
+    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, vm.names.WeakMap);
+    return {};
+}
+
+Value WeakMapConstructor::construct(Function&)
+{
+    auto& vm = this->vm();
+    if (vm.argument(0).is_nullish())
+        return WeakMap::create(global_object());
+
+    auto* weak_map = WeakMap::create(global_object());
+    auto adder = weak_map->get(vm.names.set);
+    if (vm.exception())
+        return {};
+    if (!adder.is_function()) {
+        vm.throw_exception<TypeError>(global_object(), ErrorType::NotAFunction, "'set' property of WeakMap");
+        return {};
+    }
+    get_iterator_values(global_object(), vm.argument(0), [&](Value iterator_value) {
+        if (vm.exception())
+            return IterationDecision::Break;
+        if (!iterator_value.is_object()) {
+            vm.throw_exception<TypeError>(global_object(), ErrorType::NotAnObject, String::formatted("Iterator value {}", iterator_value.to_string_without_side_effects()));
+            return IterationDecision::Break;
+        }
+        auto key = iterator_value.as_object().get(0);
+        if (vm.exception())
+            return IterationDecision::Break;
+        auto value = iterator_value.as_object().get(1);
+        if (vm.exception())
+            return IterationDecision::Break;
+        (void)vm.call(adder.as_function(), Value(weak_map), key, value);
+        return vm.exception() ? IterationDecision::Break : IterationDecision::Continue;
+    });
+    if (vm.exception())
+        return {};
+    return weak_map;
+}
+
+}