LibJS: Implement Object.getOwnPropertyNames()

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/f95a1196270

Libraries/LibJS/Runtime/ObjectConstructor.cpp

@@ -27,6 +27,7 @@
 #include <AK/Function.h>
 #include <LibJS/Heap/Heap.h>
 #include <LibJS/Interpreter.h>
+#include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/ObjectConstructor.h>
 
 namespace JS {
@@ -35,6 +36,7 @@ ObjectConstructor::ObjectConstructor()
 {
     put("prototype", interpreter().object_prototype());
 
+    put_native_function("getOwnPropertyNames", get_own_property_names);
     put_native_function("getPrototypeOf", get_prototype_of);
     put_native_function("setPrototypeOf", set_prototype_of);
 }
@@ -48,6 +50,24 @@ Value ObjectConstructor::call(Interpreter& interpreter)
     return interpreter.heap().allocate<Object>();
 }
 
+Value ObjectConstructor::get_own_property_names(Interpreter& interpreter)
+{
+    if (interpreter.call_frame().arguments.size() < 1)
+        return {};
+    auto* object = interpreter.call_frame().arguments[0].to_object(interpreter.heap());
+    if (interpreter.exception())
+        return {};
+    auto* result = interpreter.heap().allocate<Array>();
+    if (object->is_array()) {
+        auto* array = static_cast<const Array*>(object);
+        for (i32 i = 0; i < array->length(); ++i)
+            result->push(js_string(interpreter.heap(), String::number(i)));
+    }
+    for (auto& it : object->own_properties())
+        result->push(js_string(interpreter.heap(), it.key));
+    return result;
+}
+
 Value ObjectConstructor::get_prototype_of(Interpreter& interpreter)
 {
     if (interpreter.call_frame().arguments.size() < 1)

Libraries/LibJS/Runtime/ObjectConstructor.h

@@ -40,6 +40,7 @@ public:
 private:
     virtual const char* class_name() const override { return "ObjectConstructor"; }
 
+    static Value get_own_property_names(Interpreter&);
     static Value get_prototype_of(Interpreter&);
     static Value set_prototype_of(Interpreter&);
 };

Libraries/LibJS/Tests/Object.getOwnPropertyNames.js

@@ -0,0 +1,15 @@
+function assert(x) { if (!x) throw 1; }
+
+try {
+    var names = Object.getOwnPropertyNames([1, 2, 3]);
+
+    assert(names.length === 4);
+    assert(names[0] === '0');
+    assert(names[1] === '1');
+    assert(names[2] === '2');
+    assert(names[3] === 'length');
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}