Function IsInstanceOf

src/util/helpers.cpp:116–120

// native class. Each native class is identified by a unique type tag, which
// gets applied to each of its instances upon construction.
template <typename T> inline bool IsInstanceOf(Napi::Env env, Napi::Value value) {
	bool result = false;
	napi_status status = napi_check_object_type_tag(env, value.As<Napi::Object>(), &T::TYPE_TAG, &result);
	return status == napi_ok && result;
}

// Wraps a native method so that it can only be invoked on a receiver that is
// backed by the expected native class. Node-API has no equivalent of