LibJS: Begin implementing console.dir

The intent of the spec is that the output of console.dir is interactable
within the console. Our Printer implementation currently just prints the
provided object as a string, and doesn't check the provided `options`
argument. But having console.dir defined prevents exceptions from being
thrown on real websites.

Userland/Libraries/LibJS/Console.cpp

@@ -168,6 +168,26 @@ ThrowCompletionOr<Value> Console::warn()
     return js_undefined();
 }
 
+// 1.1.10. dir(item, options), https://console.spec.whatwg.org/#dir
+ThrowCompletionOr<Value> Console::dir()
+{
+    auto& vm = realm().vm();
+
+    // 1. Let object be item with generic JavaScript object formatting applied.
+    // NOTE: Generic formatting is performed by ConsoleClient::printer().
+    auto object = vm.argument(0);
+
+    // 2. Perform Printer("dir", « object », options).
+    if (m_client) {
+        MarkedVector<Value> printer_arguments { vm.heap() };
+        TRY_OR_THROW_OOM(vm, printer_arguments.try_append(object));
+
+        return m_client->printer(LogLevel::Dir, move(printer_arguments));
+    }
+
+    return js_undefined();
+}
+
 static ThrowCompletionOr<String> label_or_fallback(VM& vm, StringView fallback)
 {
     return vm.argument_count() > 0

Userland/Libraries/LibJS/Console.h

@@ -73,6 +73,7 @@ public:
     ThrowCompletionOr<Value> log();
     ThrowCompletionOr<Value> trace();
     ThrowCompletionOr<Value> warn();
+    ThrowCompletionOr<Value> dir();
     ThrowCompletionOr<Value> count();
     ThrowCompletionOr<Value> count_reset();
     ThrowCompletionOr<Value> group();

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -151,6 +151,7 @@ namespace JS {
     P(deref)                                 \
     P(description)                           \
     P(difference)                            \
+    P(dir)                                   \
     P(direction)                             \
     P(disambiguation)                        \
     P(disposed)                              \

Userland/Libraries/LibJS/Runtime/ConsoleObject.cpp

@@ -31,6 +31,7 @@ ThrowCompletionOr<void> ConsoleObject::initialize(Realm& realm)
     define_native_function(realm, vm.names.log, log, 0, attr);
     define_native_function(realm, vm.names.trace, trace, 0, attr);
     define_native_function(realm, vm.names.warn, warn, 0, attr);
+    define_native_function(realm, vm.names.dir, dir, 0, attr);
     define_native_function(realm, vm.names.count, count, 0, attr);
     define_native_function(realm, vm.names.countReset, count_reset, 0, attr);
     define_native_function(realm, vm.names.group, group, 0, attr);
@@ -99,6 +100,13 @@ JS_DEFINE_NATIVE_FUNCTION(ConsoleObject::warn)
     return console_object.console().warn();
 }
 
+// 1.1.10. dir(item, options), https://console.spec.whatwg.org/#warn
+JS_DEFINE_NATIVE_FUNCTION(ConsoleObject::dir)
+{
+    auto& console_object = *vm.current_realm()->intrinsics().console_object();
+    return console_object.console().dir();
+}
+
 // 1.2.1. count(label), https://console.spec.whatwg.org/#count
 JS_DEFINE_NATIVE_FUNCTION(ConsoleObject::count)
 {

Userland/Libraries/LibJS/Runtime/ConsoleObject.h

@@ -30,6 +30,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(log);
     JS_DECLARE_NATIVE_FUNCTION(trace);
     JS_DECLARE_NATIVE_FUNCTION(warn);
+    JS_DECLARE_NATIVE_FUNCTION(dir);
     JS_DECLARE_NATIVE_FUNCTION(count);
     JS_DECLARE_NATIVE_FUNCTION(count_reset);
     JS_DECLARE_NATIVE_FUNCTION(group);