feat(value): add null

src/engine/include/includejs/engine_context.h

@@ -21,6 +21,7 @@ class INCLUDEJS_ENGINE_EXPORT Context {
   ~Context();
 #endif
   auto make_undefined() const -> Value;
+  auto make_null() const -> Value;
   auto make_error(const std::string &message) const -> Value;
   auto make_object() const -> Value;
   auto make_promise() const -> Promise;

src/engine/include/includejs/engine_value.h

@@ -34,6 +34,7 @@ class INCLUDEJS_ENGINE_EXPORT Value {
   auto is_error() const -> bool;
   auto is_object() const -> bool;
   auto is_boolean() const -> bool;
+  auto is_null() const -> bool;
   auto to_number() const -> double;
   auto to_string() const -> std::string;
   auto to_boolean() const -> bool;

src/engine/javascript_core/engine_context.cc

@@ -29,6 +29,10 @@ auto Context::make_undefined() const -> Value {
           JSValueMakeUndefined(this->internal->context)};
 }
 
+auto Context::make_null() const -> Value {
+  return {this->internal->context, JSValueMakeNull(this->internal->context)};
+}
+
 auto Context::make_error(const std::string &message) const -> Value {
   JSStringRef message_value = JSStringCreateWithUTF8CString(message.c_str());
   JSValueRef error_arguments[]{

src/engine/javascript_core/engine_value.cc

@@ -66,6 +66,10 @@ auto Value::is_boolean() const -> bool {
   return JSValueIsBoolean(this->internal->context, this->internal->value);
 }
 
+auto Value::is_null() const -> bool {
+  return JSValueIsNull(this->internal->context, this->internal->value);
+}
+
 auto Value::to_number() const -> double {
   assert(is_number());
   JSValueRef exception = nullptr;

test/engine/CMakeLists.txt

@@ -2,7 +2,8 @@ add_executable(includejs_engine_unit
   engine_binding_test.cc
   engine_evaluate_test.cc
   engine_stacktraces_test.cc
-  engine_value_object_test.cc)
+  engine_value_object_test.cc
+  engine_value_null_test.cc)
 
 sourcemeta_includejs_add_compile_options(includejs_engine_unit)
 

test/engine/engine_value_null_test.cc

@@ -0,0 +1,16 @@
+#include <gtest/gtest.h>
+
+#include <includejs/engine.h>
+
+TEST(IncludeJS_Engine, create_null) {
+  sourcemeta::includejs::Engine engine;
+
+  auto null = engine.context().make_null();
+  EXPECT_TRUE(null.is_null());
+}
+
+TEST(IncludeJS_Engine, evaluate_null) {
+  sourcemeta::includejs::Engine engine;
+  sourcemeta::includejs::Value result{engine.evaluate("null", "index.js")};
+  EXPECT_TRUE(result.is_null());
+}