allow regular class member objects to be accessed w/o copying

include/noobject.h

@@ -624,10 +624,16 @@ template <typename T, const ReturnAttribute &RETATTR> class ToJS {
   T *object;
 
 public:
-  inline explicit ToJS(Napi::Env env, T val) : env_(env) {
+  inline explicit ToJS(Napi::Env env, T &val) : env_(env) {
     if constexpr (std::is_object_v<T> && !std::is_pod_v<T>) {
-      // C++ returned regular stack-allocated object, import to JS by copying to the heap
-      object = new T(val);
+      // C++ returned regular object
+      if constexpr (RETATTR.isNested()) {
+        // This is a nested object from a getter (for a class member object), return a nested reference
+        object = &val;
+      } else {
+        // This is a stack-allocated object, copy it to the heap
+        object = new T(val);
+      }
     } else {
       static_assert(!std::is_same<T, T>(), "Type does not have a ToJS typemap");
     }

include/nostl.h

@@ -72,7 +72,7 @@ template <typename M, typename T, const ReturnAttribute &RETATTR> class ToJSMap
   inline explicit ToJSMap(Napi::Env env, M val) : env_(env), val_(val) {}
   inline Napi::Value Get() {
     Napi::Object object = Napi::Object::New(env_);
-    for (auto const &prop : val_) {
+    for (auto &prop : val_) {
       object.Set(Napi::String::New(env_, prop.first), ToJS<T, RETATTR>(env_, prop.second).Get());
     }
     return object;

test/tests/nested.cc

@@ -8,7 +8,7 @@ NOBIND_MODULE(nested, m) {
   m.def<DateTime>("DateTime")
       .cons<Time>()
       .cons<unsigned long>()
-      // Getters of object members automatically return nested references
+      // Getters of object members references automatically return nested references
       .def<&DateTime::time>("time")
       // Explicitly return a nested reference
       .def<&DateTime::operator Time &, Nobind::ReturnNested>("get");