diff --git a/dependencies.list b/dependencies.list
index 7211a5f8..be39372f 100644
--- a/dependencies.list
+++ b/dependencies.list
@@ -1,5 +1,5 @@
 PACKAGE_NAME=realm-js
 VERSION=1.3.1
-REALM_CORE_VERSION=2.6.0
-REALM_SYNC_VERSION=1.8.3
-REALM_OBJECT_SERVER_VERSION=1.3.0
+REALM_CORE_VERSION=2.8.1
+REALM_SYNC_VERSION=1.9.2
+REALM_OBJECT_SERVER_VERSION=1.7.1
diff --git a/src/js_list.hpp b/src/js_list.hpp
index 14b73f32..c60e3028 100644
--- a/src/js_list.hpp
+++ b/src/js_list.hpp
@@ -19,6 +19,7 @@
 #pragma once
 
 #include "js_collection.hpp"
+#include "js_object_accessor.hpp"
 #include "js_realm_object.hpp"
 #include "js_results.hpp"
 #include "js_types.hpp"
@@ -32,12 +33,15 @@
 namespace realm {
 namespace js {
 
+template<typename JSEngine>
+class NativeAccessor;
+
 template<typename T>
 class List : public realm::List {
   public:
     List(std::shared_ptr<realm::Realm> r, const ObjectSchema& s, LinkViewRef l) noexcept : realm::List(r, l) {}
     List(const realm::List &l) : realm::List(l) {}
-    
+
     std::vector<std::pair<Protected<typename T::Function>, NotificationToken>> m_notification_tokens;
 };
 
@@ -104,7 +108,7 @@ typename T::Object ListClass<T>::create_instance(ContextType ctx, realm::List li
 }
 
 template<typename T>
-void ListClass<T>::get_length(ContextType ctx, ObjectType object, ReturnValue &return_value) {
+void ListClass<T>::get_length(ContextType, ObjectType object, ReturnValue &return_value) {
     auto list = get_internal<T, ListClass<T>>(object);
     return_value.set((uint32_t)list->size());
 }
@@ -120,7 +124,8 @@ void ListClass<T>::get_index(ContextType ctx, ObjectType object, uint32_t index,
 template<typename T>
 bool ListClass<T>::set_index(ContextType ctx, ObjectType object, uint32_t index, ValueType value) {
     auto list = get_internal<T, ListClass<T>>(object);
-    list->set(ctx, value, index);
+    NativeAccessor<T> accessor(ctx, list->get_realm(), &list->get_object_schema());
+    list->set(accessor, index, value);
     return true;
 }
 
@@ -129,8 +134,9 @@ void ListClass<T>::push(ContextType ctx, FunctionType, ObjectType this_object, s
     validate_argument_count_at_least(argc, 1);
 
     auto list = get_internal<T, ListClass<T>>(this_object);
+    NativeAccessor<T> accessor(ctx, list->get_realm(), &list->get_object_schema());
     for (size_t i = 0; i < argc; i++) {
-        list->add(ctx, arguments[i]);
+        list->add(accessor, arguments[i]);
     }
 
     return_value.set((uint32_t)list->size());
@@ -160,8 +166,9 @@ void ListClass<T>::unshift(ContextType ctx, FunctionType, ObjectType this_object
     validate_argument_count_at_least(argc, 1);
 
     auto list = get_internal<T, ListClass<T>>(this_object);
+    NativeAccessor<T> accessor(ctx, list->get_realm(), &list->get_object_schema());
     for (size_t i = 0; i < argc; i++) {
-        list->insert(ctx, arguments[i], i);
+        list->insert(accessor, i, arguments[i]);
     }
 
     return_value.set((uint32_t)list->size());
@@ -207,6 +214,7 @@ void ListClass<T>::splice(ContextType ctx, FunctionType, ObjectType this_object,
     std::vector<ValueType> removed_objects;
     removed_objects.reserve(remove);
 
+    NativeAccessor<T> accessor(ctx, list->get_realm(), &list->get_object_schema());
     for (size_t i = 0; i < remove; i++) {
         auto realm_object = realm::Object(list->get_realm(), list->get_object_schema(), list->get(index));
 
@@ -214,7 +222,7 @@ void ListClass<T>::splice(ContextType ctx, FunctionType, ObjectType this_object,
         list->remove(index);
     }
     for (size_t i = 2; i < argc; i++) {
-        list->insert(ctx, arguments[i], index + i - 2);
+        list->insert(accessor, index + i - 2, arguments[i]);
     }
 
     return_value.set(Object::create_array(ctx, removed_objects));
diff --git a/src/js_object_accessor.hpp b/src/js_object_accessor.hpp
index d9ec7f1b..6fb3b043 100644
--- a/src/js_object_accessor.hpp
+++ b/src/js_object_accessor.hpp
@@ -23,136 +23,235 @@
 #include "js_schema.hpp"
 
 namespace realm {
+class List;
+class Object;
+class ObjectSchema;
+class Realm;
+class Results;
+struct Property;
+
 namespace js {
+namespace _impl {
+template<typename JSEngine, typename T>
+struct Unbox;
+}
 
-template<typename T>
-struct NativeAccessor {
-    using ContextType = typename T::Context;
-    using ObjectType = typename T::Object;
-    using ValueType = typename T::Value;
-    using Object = js::Object<T>;
-    using Value = js::Value<T>;
+template<typename JSEngine>
+class NativeAccessor {
+public:
+    using ContextType = typename JSEngine::Context;
+    using ObjectType = typename JSEngine::Object;
+    using ValueType = typename JSEngine::Value;
+    using Object = js::Object<JSEngine>;
+    using Value = js::Value<JSEngine>;
+    using OptionalValue = util::Optional<ValueType>;
 
-    static bool dict_has_value_for_key(ContextType ctx, ValueType dict, const std::string &prop_name) {
-        ObjectType object = Value::validated_to_object(ctx, dict);
-        return Object::has_property(ctx, object, prop_name);
-    }
-    static ValueType dict_value_for_key(ContextType ctx, ValueType dict, const std::string &prop_name) {
-        ObjectType object = Value::validated_to_object(ctx, dict);
-        return Object::get_property(ctx, object, prop_name);
-    }
+    NativeAccessor(ContextType ctx, std::shared_ptr<Realm> realm=nullptr, const ObjectSchema* object_schema=nullptr)
+    : m_ctx(ctx), m_realm(std::move(realm)), m_object_schema(object_schema) { }
 
-    static bool has_default_value_for_property(ContextType ctx, realm::Realm *realm, const ObjectSchema &object_schema, const std::string &prop_name) {
-        auto defaults = get_delegate<T>(realm)->m_defaults[object_schema.name];
-        return defaults.count(prop_name) != 0;
-    }
-    static ValueType default_value_for_property(ContextType ctx, realm::Realm *realm, const ObjectSchema &object_schema, const std::string &prop_name) {
-        auto defaults = get_delegate<T>(realm)->m_defaults[object_schema.name];
-        return defaults.at(prop_name);
-    }
+    NativeAccessor(NativeAccessor& parent, const Property& prop)
+    : m_ctx(parent.m_ctx)
+    , m_realm(parent.m_realm)
+    , m_object_schema(&*m_realm->schema().find(prop.object_type))
+    { }
 
-    // These must be implemented for each JS engine.
-    static std::string to_binary(ContextType, ValueType &);
-    static ValueType from_binary(ContextType, BinaryData);
-
-    static bool to_bool(ContextType ctx, ValueType &value) {
-        return Value::validated_to_boolean(ctx, value, "Property");
-    }
-    static ValueType from_bool(ContextType ctx, bool boolean) {
-        return Value::from_boolean(ctx, boolean);
-    }
-    static long long to_long(ContextType ctx, ValueType &value) {
-        return Value::validated_to_number(ctx, value, "Property");
-    }
-    static ValueType from_long(ContextType ctx, long long number) {
-        return Value::from_number(ctx, number);
-    }
-    static float to_float(ContextType ctx, ValueType &value) {
-        return Value::validated_to_number(ctx, value, "Property");
-    }
-    static ValueType from_float(ContextType ctx, float number) {
-        return Value::from_number(ctx, number);
-    }
-    static double to_double(ContextType ctx, ValueType &value) {
-        return Value::validated_to_number(ctx, value, "Property");
-    }
-    static ValueType from_double(ContextType ctx, double number) {
-        return Value::from_number(ctx, number);
-    }
-    static std::string to_string(ContextType ctx, ValueType &value) {
-        return Value::validated_to_string(ctx, value, "Property");
-    }
-    static ValueType from_string(ContextType ctx, StringData string) {
-        return Value::from_string(ctx, string.data());
-    }
-    static Timestamp to_timestamp(ContextType ctx, ValueType &value) {
-        ObjectType date = Value::validated_to_date(ctx, value, "Property");
-        double milliseconds = Value::to_number(ctx, date);
-        int64_t seconds = milliseconds / 1000;
-        int32_t nanoseconds = ((int64_t)milliseconds % 1000) * 1000000;
-        return Timestamp(seconds, nanoseconds);
-    }
-    static ValueType from_timestamp(ContextType ctx, Timestamp ts) {
-        return Object::create_date(ctx, ts.get_seconds() * 1000 + ts.get_nanoseconds() / 1000000);
-    }
-
-    static bool is_null(ContextType ctx, ValueType &value) {
-        return Value::is_null(ctx, value) || Value::is_undefined(ctx, value);
-    }
-    static ValueType null_value(ContextType ctx) {
-        return Value::from_null(ctx);
-    }
-
-    static size_t to_object_index(ContextType ctx, SharedRealm realm, ValueType &value, const std::string &type, bool try_update) {
-        ObjectType object = Value::validated_to_object(ctx, value);
-        if (Object::template is_instance<RealmObjectClass<T>>(ctx, object)) {
-            auto realm_object = get_internal<T, RealmObjectClass<T>>(object);
-            if (realm_object->realm() == realm) {
-                return realm_object->row().get_index();
-            }
+    OptionalValue value_for_property(ValueType dict, std::string const& prop_name, size_t) {
+        ObjectType object = Value::validated_to_object(m_ctx, dict);
+        if (!Object::has_property(m_ctx, object, prop_name)) {
+            return util::none;
         }
+        return Object::get_property(m_ctx, object, prop_name);
+    }
 
-        auto object_schema = realm->schema().find(type);
-        if (Value::is_array(ctx, object)) {
-            object = Schema<T>::dict_for_property_array(ctx, *object_schema, object);
+    OptionalValue default_value_for_property(const ObjectSchema &object_schema, const std::string &prop_name) {
+        auto defaults = get_delegate<JSEngine>(m_realm.get())->m_defaults[object_schema.name];
+        auto it = defaults.find(prop_name);
+        return it != defaults.end() ? util::make_optional(ValueType(it->second)) : util::none;
+    }
+
+    template<typename T>
+    T unbox(ValueType value, bool create = false, bool update = false);
+
+    ValueType box(bool boolean)      { return Value::from_boolean(m_ctx, boolean); }
+    ValueType box(int64_t number)    { return Value::from_number(m_ctx, number); }
+    ValueType box(float number)      { return Value::from_number(m_ctx, number); }
+    ValueType box(double number)     { return Value::from_number(m_ctx, number); }
+    ValueType box(StringData string) { return Value::from_string(m_ctx, string.data()); }
+    ValueType box(Mixed)             { throw std::runtime_error("'Any' type is unsupported"); }
+
+    ValueType box(BinaryData);
+    ValueType box(Timestamp ts) {
+        return Object::create_date(m_ctx, ts.get_seconds() * 1000 + ts.get_nanoseconds() / 1000000);
+    }
+    ValueType box(realm::Object realm_object) {
+        return RealmObjectClass<JSEngine>::create_instance(m_ctx, std::move(realm_object));
+    }
+    ValueType box(realm::List list) {
+        return ListClass<JSEngine>::create_instance(m_ctx, std::move(list));
+    }
+    ValueType box(realm::Results results) {
+        return ResultsClass<JSEngine>::create_instance(m_ctx, std::move(results));
+    }
+
+    bool is_null(ValueType const& value) {
+        return Value::is_null(m_ctx, value) || Value::is_undefined(m_ctx, value);
+    }
+    ValueType null_value() {
+        return Value::from_null(m_ctx);
+    }
+
+    template<typename Fn>
+    void enumerate_list(ValueType& value, Fn&& func) {
+        auto obj = Value::validated_to_object(m_ctx, value);
+        uint32_t size = Object::validated_get_length(m_ctx, obj);
+        for (uint32_t i = 0; i < size; ++i) {
+            func(Object::validated_get_object(m_ctx, obj, i));
         }
-
-        auto child = realm::Object::create<ValueType>(ctx, realm, *object_schema, static_cast<ValueType>(object), try_update);
-        return child.row().get_index();
-    }
-    static size_t to_existing_object_index(ContextType ctx, SharedRealm realm, ValueType &value) {
-        ObjectType object = Value::validated_to_object(ctx, value);
-        if (!Object::template is_instance<RealmObjectClass<T>>(ctx, object)) {
-            throw std::runtime_error("object is not a Realm Object");
-        }
-        
-        auto realm_object = get_internal<T, RealmObjectClass<T>>(object);
-        if (realm_object->realm() != realm) {
-            throw std::runtime_error("Realm object is from another Realm");
-
-        }
-        return realm_object->row().get_index();
-    }
-    static ValueType from_object(ContextType ctx, realm::Object realm_object) {
-        return RealmObjectClass<T>::create_instance(ctx, std::move(realm_object));
     }
 
-    static size_t list_size(ContextType ctx, ValueType &value) {
-        return Object::validated_get_length(ctx, Value::validated_to_object(ctx, value));
+    bool allow_missing(ValueType const&) const noexcept { return false; }
+    void will_change(realm::Object&, realm::Property const&) { }
+    void did_change() { }
+
+    std::string print(ValueType const&) { return "not implemented"; }
+
+private:
+    ContextType m_ctx;
+    std::shared_ptr<Realm> m_realm;
+    const ObjectSchema* m_object_schema = nullptr;
+    std::string m_string_buffer;
+
+    template<typename, typename>
+    friend struct _impl::Unbox;
+};
+
+namespace _impl {
+template<typename JSEngine>
+struct Unbox<JSEngine, bool> {
+    static bool call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_boolean(ctx->m_ctx, value, "Property");
     }
-    static ValueType list_value_at_index(ContextType ctx, ValueType &value, size_t index) {
-        return Object::validated_get_object(ctx, Value::validated_to_object(ctx, value), (uint32_t)index);
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, int64_t> {
+    static int64_t call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
-    static ValueType from_list(ContextType ctx, realm::List list) {
-        return ListClass<T>::create_instance(ctx, std::move(list));
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, float> {
+    static float call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
-    static ValueType from_results(ContextType ctx, realm::Results results) {
-        return ResultsClass<T>::create_instance(ctx, std::move(results));
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, double> {
+    static double call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
-    static Mixed to_mixed(ContextType ctx, ValueType &val) {
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, util::Optional<bool>> {
+    static util::Optional<bool> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_boolean(ctx->m_ctx, value, "Property");
+}
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, util::Optional<int64_t>> {
+    static util::Optional<int64_t> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
+}
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, util::Optional<float>> {
+    static util::Optional<float> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
+}
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, util::Optional<double>> {
+    static util::Optional<double> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
+}
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, StringData> {
+    static StringData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        ctx->m_string_buffer = js::Value<JSEngine>::validated_to_string(ctx->m_ctx, value, "Property");
+        return ctx->m_string_buffer;
+    }
+};
+
+// Need separate implementations per-engine
+template<typename JSEngine>
+struct Unbox<JSEngine, BinaryData> {
+    static BinaryData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value value, bool, bool);
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, Mixed> {
+    static Mixed call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
         throw std::runtime_error("'Any' type is unsupported");
     }
 };
 
+template<typename JSEngine>
+struct Unbox<JSEngine, Timestamp> {
+    static Timestamp call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+        auto date = js::Value<JSEngine>::validated_to_date(ctx->m_ctx, value, "Property");
+        double milliseconds = js::Value<JSEngine>::to_number(ctx->m_ctx, date);
+        int64_t seconds = milliseconds / 1000;
+        int32_t nanoseconds = ((int64_t)milliseconds % 1000) * 1000000;
+        return Timestamp(seconds, nanoseconds);
+    }
+};
+
+template<typename JSEngine>
+struct Unbox<JSEngine, RowExpr> {
+    static RowExpr call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool create, bool try_update) {
+        using Value = js::Value<JSEngine>;
+        using ValueType = typename JSEngine::Value;
+
+        auto object = Value::validated_to_object(ctx->m_ctx, value);
+        if (js::Object<JSEngine>::template is_instance<RealmObjectClass<JSEngine>>(ctx->m_ctx, object)) {
+            auto realm_object = get_internal<JSEngine, RealmObjectClass<JSEngine>>(object);
+            if (realm_object->realm() == ctx->m_realm) {
+                return realm_object->row();
+            }
+            if (!create) {
+                throw std::runtime_error("Realm object is from another Realm");
+            }
+        }
+        else if (!create) {
+            throw std::runtime_error("object is not a Realm Object");
+        }
+
+        if (Value::is_array(ctx->m_ctx, object)) {
+            object = Schema<JSEngine>::dict_for_property_array(ctx->m_ctx, *ctx->m_object_schema, object);
+        }
+
+        auto child = realm::Object::create<ValueType>(*ctx, ctx->m_realm,
+                                                      *ctx->m_object_schema,
+                                                      static_cast<ValueType>(object), try_update);
+        return child.row();
+    }
+};
+} // namespace _impl
+
+template<typename T>
+template<typename U>
+U NativeAccessor<T>::unbox(ValueType value, bool create, bool update) {
+    return _impl::Unbox<T, U>::call(this, std::move(value), create, update);
+}
+
+
 } // js
 } // realm
diff --git a/src/js_realm.hpp b/src/js_realm.hpp
index 16769b7f..5d2a0aa4 100644
--- a/src/js_realm.hpp
+++ b/src/js_realm.hpp
@@ -79,10 +79,6 @@ class RealmDelegate : public BindingContext {
     virtual void did_change(std::vector<ObserverState> const& observers, std::vector<void*> const& invalidated, bool version_changed) {
         notify("change");
     }
-    virtual std::vector<ObserverState> get_observed_rows() {
-        return std::vector<ObserverState>();
-    }
-    virtual void will_change(std::vector<ObserverState> const& observers, std::vector<void*> const& invalidated) {}
 
     RealmDelegate(std::weak_ptr<realm::Realm> realm, GlobalContextType ctx) : m_context(ctx), m_realm(realm) {}
 
@@ -159,7 +155,7 @@ class RealmClass : public ClassDefinition<T, SharedRealm, ObservableClass<T>> {
     using Object = js::Object<T>;
     using Value = js::Value<T>;
     using ReturnValue = js::ReturnValue<T>;
-    using NativeAccessor = realm::NativeAccessor<ValueType, ContextType>;
+    using NativeAccessor = realm::js::NativeAccessor<T>;
 
 public:
     using ObjectDefaultsMap = typename Schema<T>::ObjectDefaultsMap;
@@ -353,8 +349,9 @@ void RealmClass<T>::constructor(ContextType ctx, ObjectType this_object, size_t
             static const String encryption_key_string = "encryptionKey";
             ValueType encryption_key_value = Object::get_property(ctx, object, encryption_key_string);
             if (!Value::is_undefined(ctx, encryption_key_value)) {
-                std::string encryption_key = NativeAccessor::to_binary(ctx, encryption_key_value);
-                config.encryption_key = std::vector<char>(encryption_key.begin(), encryption_key.end());
+                NativeAccessor accessor(ctx);
+                auto encryption_key = accessor.template unbox<BinaryData>(encryption_key_value);
+                config.encryption_key.assign(encryption_key.data(), encryption_key.data() + encryption_key.size());
             }
 
 #if REALM_ENABLE_SYNC
@@ -469,9 +466,9 @@ void RealmClass<T>::schema_version(ContextType ctx, FunctionType, ObjectType thi
     realm::Realm::Config config;
     config.path = normalize_realm_path(Value::validated_to_string(ctx, arguments[0]));
     if (argc == 2) {
-        auto encryptionKeyValue = arguments[1];
-        std::string encryptionKey = NativeAccessor::to_binary(ctx, encryptionKeyValue);
-        config.encryption_key = std::vector<char>(encryptionKey.begin(), encryptionKey.end());
+        NativeAccessor accessor(ctx);
+        auto encryption_key = accessor.template unbox<BinaryData>(arguments[1]);
+        config.encryption_key.assign(encryption_key.data(), encryption_key.data() + encryption_key.size());
     }
 
     auto version = realm::Realm::get_schema_version(config);
@@ -556,8 +553,9 @@ void RealmClass<T>::wait_for_download_completion(ContextType ctx, FunctionType,
         static const String encryption_key_string = "encryptionKey";
         ValueType encryption_key_value = Object::get_property(ctx, config_object, encryption_key_string);
         if (!Value::is_undefined(ctx, encryption_key_value)) {
-            std::string encryption_key = NativeAccessor::to_binary(ctx, encryption_key_value);
-            config.encryption_key = std::vector<char>(encryption_key.begin(), encryption_key.end());
+            NativeAccessor accessor(ctx);
+            auto encryption_key = accessor.template unbox<BinaryData>(encryption_key_value);
+            config.encryption_key.assign(encryption_key.data(), encryption_key.data() + encryption_key.size());
         }
         
         Protected<ObjectType> thiz(ctx, this_object);
@@ -634,7 +632,8 @@ void RealmClass<T>::object_for_primary_key(ContextType ctx, FunctionType, Object
     SharedRealm realm = *get_internal<T, RealmClass<T>>(this_object);
     std::string object_type;
     auto &object_schema = validated_object_schema_for_value(ctx, realm, arguments[0], object_type);
-    auto realm_object = realm::Object::get_for_primary_key(ctx, realm, object_schema, arguments[1]);
+    NativeAccessor accessor(ctx, realm);
+    auto realm_object = realm::Object::get_for_primary_key(accessor, realm, object_schema, arguments[1]);
 
     if (realm_object.is_valid()) {
         return_value.set(RealmObjectClass<T>::create_instance(ctx, std::move(realm_object)));
@@ -662,7 +661,8 @@ void RealmClass<T>::create(ContextType ctx, FunctionType, ObjectType this_object
         update = Value::validated_to_boolean(ctx, arguments[2], "update");
     }
 
-    auto realm_object = realm::Object::create<ValueType>(ctx, realm, object_schema, object, update);
+    NativeAccessor accessor(ctx, realm);
+    auto realm_object = realm::Object::create<ValueType>(accessor, realm, object_schema, object, update);
     return_value.set(RealmObjectClass<T>::create_instance(ctx, std::move(realm_object)));
 }
 
@@ -799,4 +799,4 @@ void RealmClass<T>::close(ContextType ctx, FunctionType, ObjectType this_object,
 }
 
 } // js
-} // realm
\ No newline at end of file
+} // realm
diff --git a/src/js_realm_object.hpp b/src/js_realm_object.hpp
index 93405205..44ab4039 100644
--- a/src/js_realm_object.hpp
+++ b/src/js_realm_object.hpp
@@ -28,6 +28,8 @@
 namespace realm {
 namespace js {
 
+template<typename> class NativeAccessor;
+
 template<typename T>
 struct RealmObjectClass : ClassDefinition<T, realm::Object> {
     using ContextType = typename T::Context;
@@ -94,7 +96,9 @@ template<typename T>
 void RealmObjectClass<T>::get_property(ContextType ctx, ObjectType object, const String &property, ReturnValue &return_value) {
     try {
         auto realm_object = get_internal<T, RealmObjectClass<T>>(object);
-        auto result = realm_object->template get_property_value<ValueType>(ctx, property);
+        NativeAccessor<T> accessor(ctx);
+        std::string name = property;
+        auto result = realm_object->template get_property_value<ValueType>(accessor, name);
         return_value.set(result);
     } catch (InvalidPropertyException &ex) {
         // getters for nonexistent properties in JS should always return undefined
@@ -111,7 +115,8 @@ bool RealmObjectClass<T>::set_property(ContextType ctx, ObjectType object, const
     }
 
     try {
-        realm_object->set_property_value(ctx, property_name, value, true);
+        NativeAccessor<T> accessor(ctx, realm_object->realm());
+        realm_object->set_property_value(accessor, property_name, value, true);
     }
     catch (TypeErrorException &ex) {
         throw TypeErrorException(realm_object->get_object_schema().name + "." + property_name, ex.type());
diff --git a/src/js_results.hpp b/src/js_results.hpp
index d3e904f7..317e166a 100644
--- a/src/js_results.hpp
+++ b/src/js_results.hpp
@@ -30,6 +30,9 @@
 namespace realm {
 namespace js {
 
+template<typename>
+class NativeAccessor;
+
 template<typename T>
 class Results : public realm::Results {
   public:
@@ -117,10 +120,9 @@ typename T::Object ResultsClass<T>::create_filtered(ContextType ctx, const U &co
     auto const &realm = collection.get_realm();
     auto const &object_schema = collection.get_object_schema();
 
-    std::vector<ValueType> args(&arguments[1], &arguments[argc]);
-
     parser::Predicate predicate = parser::parse(query_string);
-    query_builder::ArgumentConverter<ValueType, ContextType> converter(ctx, realm, args);
+    NativeAccessor<T> accessor(ctx, realm);
+    query_builder::ArgumentConverter<ValueType, NativeAccessor<T>> converter(accessor, &arguments[1], argc - 1);
     query_builder::apply_predicate(query, predicate, converter, realm->schema(), object_schema.name);
 
     return create_instance(ctx, realm::Results(realm, std::move(query)));
diff --git a/src/js_sync.hpp b/src/js_sync.hpp
index 427a1268..400a3d5b 100644
--- a/src/js_sync.hpp
+++ b/src/js_sync.hpp
@@ -51,7 +51,6 @@ class UserClass : public ClassDefinition<T, SharedUser> {
     using Value = js::Value<T>;
     using Function = js::Function<T>;
     using ReturnValue = js::ReturnValue<T>;
-    using NativeAccessor = realm::NativeAccessor<ValueType, ContextType>;
 
 public:
     std::string const name = "User";
@@ -337,7 +336,6 @@ class SyncClass : public ClassDefinition<T, void *> {
     using Value = js::Value<T>;
     using Function = js::Function<T>;
     using ReturnValue = js::ReturnValue<T>;
-    using NativeAccessor = realm::NativeAccessor<ValueType, ContextType>;
 
 public:
     std::string const name = "Sync";
diff --git a/src/jsc/jsc_object_accessor.hpp b/src/jsc/jsc_object_accessor.hpp
index d210d90a..7a02f6d6 100644
--- a/src/jsc/jsc_object_accessor.hpp
+++ b/src/jsc/jsc_object_accessor.hpp
@@ -24,13 +24,12 @@
 namespace realm {
 
 // Specialize a native accessor class for JSC.
-template<>
-class NativeAccessor<jsc::Types::Value, jsc::Types::Context> : public js::NativeAccessor<jsc::Types> {};
 
 namespace js {
 
 template<>
-inline std::string NativeAccessor<jsc::Types>::to_binary(JSContextRef ctx, JSValueRef &value) {
+template<>
+inline BinaryData NativeAccessor<jsc::Types>::unbox(ValueType value, bool, bool) {
     static jsc::String s_array_buffer = "ArrayBuffer";
     static jsc::String s_buffer = "buffer";
     static jsc::String s_byte_length = "byteLength";
@@ -38,25 +37,25 @@ inline std::string NativeAccessor<jsc::Types>::to_binary(JSContextRef ctx, JSVal
     static jsc::String s_is_view = "isView";
     static jsc::String s_uint8_array = "Uint8Array";
 
-    JSObjectRef global_object = JSContextGetGlobalObject(ctx);
-    JSObjectRef array_buffer_constructor = jsc::Object::validated_get_constructor(ctx, global_object, s_array_buffer);
-    JSObjectRef uint8_array_constructor = jsc::Object::validated_get_constructor(ctx, global_object, s_uint8_array);
+    JSObjectRef global_object = JSContextGetGlobalObject(m_ctx);
+    JSObjectRef array_buffer_constructor = jsc::Object::validated_get_constructor(m_ctx, global_object, s_array_buffer);
+    JSObjectRef uint8_array_constructor = jsc::Object::validated_get_constructor(m_ctx, global_object, s_uint8_array);
     JSValueRef uint8_array_arguments[3];
     uint32_t uint8_array_argc = 0;
 
     // Value should either be an ArrayBuffer or ArrayBufferView (i.e. TypedArray or DataView).
-    if (JSValueIsInstanceOfConstructor(ctx, value, array_buffer_constructor, nullptr)) {
+    if (JSValueIsInstanceOfConstructor(m_ctx, value, array_buffer_constructor, nullptr)) {
         uint8_array_arguments[0] = value;
         uint8_array_argc = 1;
     }
-    else if (JSObjectRef object = JSValueToObject(ctx, value, nullptr)) {
+    else if (JSObjectRef object = JSValueToObject(m_ctx, value, nullptr)) {
         // Check if value is an ArrayBufferView by calling ArrayBuffer.isView(val).
-        JSValueRef is_view = jsc::Object::call_method(ctx, array_buffer_constructor, s_is_view, 1, &object);
+        JSValueRef is_view = jsc::Object::call_method(m_ctx, array_buffer_constructor, s_is_view, 1, &object);
 
-        if (jsc::Value::to_boolean(ctx, is_view)) {
-            uint8_array_arguments[0] = jsc::Object::validated_get_object(ctx, object, s_buffer);
-            uint8_array_arguments[1] = jsc::Object::get_property(ctx, object, s_byte_offset);
-            uint8_array_arguments[2] = jsc::Object::get_property(ctx, object, s_byte_length);
+        if (jsc::Value::to_boolean(m_ctx, is_view)) {
+            uint8_array_arguments[0] = jsc::Object::validated_get_object(m_ctx, object, s_buffer);
+            uint8_array_arguments[1] = jsc::Object::get_property(m_ctx, object, s_byte_offset);
+            uint8_array_arguments[2] = jsc::Object::get_property(m_ctx, object, s_byte_length);
             uint8_array_argc = 3;
         }
     }
@@ -65,34 +64,34 @@ inline std::string NativeAccessor<jsc::Types>::to_binary(JSContextRef ctx, JSVal
         throw std::runtime_error("Can only convert ArrayBuffer and TypedArray objects to binary");
     }
 
-    JSObjectRef uint8_array = jsc::Function::construct(ctx, uint8_array_constructor, uint8_array_argc, uint8_array_arguments);
-    uint32_t byte_count = jsc::Object::validated_get_length(ctx, uint8_array);
-    std::string bytes(byte_count, 0);
+    JSObjectRef uint8_array = jsc::Function::construct(m_ctx, uint8_array_constructor, uint8_array_argc, uint8_array_arguments);
+    uint32_t byte_count = jsc::Object::validated_get_length(m_ctx, uint8_array);
+    m_string_buffer.resize(byte_count);
 
     for (uint32_t i = 0; i < byte_count; i++) {
-        JSValueRef byteValue = jsc::Object::get_property(ctx, uint8_array, i);
-        bytes[i] = jsc::Value::to_number(ctx, byteValue);
+        JSValueRef byteValue = jsc::Object::get_property(m_ctx, uint8_array, i);
+        m_string_buffer[i] = jsc::Value::to_number(m_ctx, byteValue);
     }
 
-    return bytes;
+    return BinaryData(m_string_buffer.data(), m_string_buffer.size());
 }
 
 template<>
-inline JSValueRef NativeAccessor<jsc::Types>::from_binary(JSContextRef ctx, BinaryData data) {
+inline JSValueRef NativeAccessor<jsc::Types>::box(BinaryData data) {
     static jsc::String s_buffer = "buffer";
     static jsc::String s_uint8_array = "Uint8Array";
 
     size_t byte_count = data.size();
-    JSValueRef byte_count_value = jsc::Value::from_number(ctx, byte_count);
-    JSObjectRef uint8_array_constructor = jsc::Object::validated_get_constructor(ctx, JSContextGetGlobalObject(ctx), s_uint8_array);
-    JSObjectRef uint8_array = jsc::Function::construct(ctx, uint8_array_constructor, 1, &byte_count_value);
+    JSValueRef byte_count_value = jsc::Value::from_number(m_ctx, byte_count);
+    JSObjectRef uint8_array_constructor = jsc::Object::validated_get_constructor(m_ctx, JSContextGetGlobalObject(m_ctx), s_uint8_array);
+    JSObjectRef uint8_array = jsc::Function::construct(m_ctx, uint8_array_constructor, 1, &byte_count_value);
 
     for (uint32_t i = 0; i < byte_count; i++) {
-        JSValueRef num = jsc::Value::from_number(ctx, data[i]);
-        jsc::Object::set_property(ctx, uint8_array, i, num);
+        JSValueRef num = jsc::Value::from_number(m_ctx, data[i]);
+        jsc::Object::set_property(m_ctx, uint8_array, i, num);
     }
     
-    return jsc::Object::validated_get_object(ctx, uint8_array, s_buffer);
+    return jsc::Object::validated_get_object(m_ctx, uint8_array, s_buffer);
 }
 
 } // js
diff --git a/src/node/node_object_accessor.hpp b/src/node/node_object_accessor.hpp
index 029ffdd0..9c338496 100644
--- a/src/node/node_object_accessor.hpp
+++ b/src/node/node_object_accessor.hpp
@@ -24,38 +24,39 @@
 namespace realm {
 
 // Specialize a native accessor class for Node.
-template<>
-class NativeAccessor<node::Types::Value, node::Types::Context> : public js::NativeAccessor<node::Types> {};
-
 namespace js {
 
 template<>
-inline std::string NativeAccessor<node::Types>::to_binary(v8::Isolate* isolate, v8::Local<v8::Value> &value) {
-    if (Value::is_array_buffer(isolate, value)) {
+template<>
+inline BinaryData NativeAccessor<node::Types>::unbox(ValueType value, bool, bool) {
+    if (Value::is_array_buffer(m_ctx, value)) {
         // TODO: This probably needs some abstraction for older V8.
 #if REALM_V8_ARRAY_BUFFER_API
         v8::Local<v8::ArrayBuffer> array_buffer = value.As<v8::ArrayBuffer>();
         v8::ArrayBuffer::Contents contents = array_buffer->GetContents();
 
-        return std::string(static_cast<char*>(contents.Data()), contents.ByteLength());
+        m_string_buffer = std::string(static_cast<char*>(contents.Data()), contents.ByteLength());
 #else
         // TODO: Implement this for older V8
 #endif
     }
-    else if (Value::is_array_buffer_view(isolate, value)) {
+    else if (Value::is_array_buffer_view(m_ctx, value)) {
         Nan::TypedArrayContents<char> contents(value);
 
-        return std::string(*contents, contents.length());
+        m_string_buffer = std::string(*contents, contents.length());
     }
     else if (::node::Buffer::HasInstance(value)) {
-        return std::string(::node::Buffer::Data(value), ::node::Buffer::Length(value));
+        m_string_buffer = std::string(::node::Buffer::Data(value), ::node::Buffer::Length(value));
+    }
+    else {
+        throw std::runtime_error("Can only convert Buffer, ArrayBuffer, and TypedArray objects to binary");
     }
 
-    throw std::runtime_error("Can only convert Buffer, ArrayBuffer, and TypedArray objects to binary");
+    return BinaryData(m_string_buffer.data(), m_string_buffer.size());
 }
 
 template<>
-inline v8::Local<v8::Value> NativeAccessor<node::Types>::from_binary(v8::Isolate* isolate, BinaryData data) {
+inline v8::Local<v8::Value> NativeAccessor<node::Types>::box(BinaryData data) {
 #if REALM_V8_ARRAY_BUFFER_API
     size_t byte_count = data.size();
     void* bytes = nullptr;
@@ -65,7 +66,7 @@ inline v8::Local<v8::Value> NativeAccessor<node::Types>::from_binary(v8::Isolate
     }
 
     // An "internalized" ArrayBuffer will free the malloc'd memory when garbage collected.
-    return v8::ArrayBuffer::New(isolate, bytes, byte_count, v8::ArrayBufferCreationMode::kInternalized);
+    return v8::ArrayBuffer::New(m_ctx, bytes, byte_count, v8::ArrayBufferCreationMode::kInternalized);
 #else
     // TODO: Implement this for older V8
 #endif
diff --git a/src/object-store b/src/object-store
index 872a154b..6decdfbb 160000
--- a/src/object-store
+++ b/src/object-store
@@ -1 +1 @@
-Subproject commit 872a154b1bfd843f7dad98cab73e23a5aff2ee66
+Subproject commit 6decdfbb88494908c8116b64b21c8715175fc2f3
diff --git a/src/rpc.cpp b/src/rpc.cpp
index bec700d5..77ba8cb1 100644
--- a/src/rpc.cpp
+++ b/src/rpc.cpp
@@ -32,7 +32,7 @@
 using namespace realm;
 using namespace realm::rpc;
 
-using Accessor = NativeAccessor<JSValueRef, JSContextRef>;
+using Accessor = realm::js::NativeAccessor<jsc::Types>;
 
 static const char * const RealmObjectTypesData = "data";
 static const char * const RealmObjectTypesDate = "date";
@@ -413,7 +413,8 @@ json RPCServer::serialize_json_value(JSValueRef js_value) {
         return {{"value", array}};
     }
     else if (jsc::Value::is_array_buffer(m_context, js_object)) {
-        std::string data = Accessor::to_binary(m_context, js_value);
+        Accessor accessor(m_context);
+        auto data = accessor.unbox<realm::BinaryData>(js_value);
         return {
             {"type", RealmObjectTypesData},
             {"value", base64_encode((unsigned char *)data.data(), data.size())},
@@ -511,7 +512,7 @@ JSValueRef RPCServer::deserialize_json_value(const json dict) {
             if (!base64_decode(value.get<std::string>(), &bytes)) {
                 throw std::runtime_error("Failed to decode base64 encoded data");
             }
-            return Accessor::from_binary(m_context, realm::BinaryData(bytes));
+            return Accessor(m_context).box(realm::BinaryData(bytes.data(), bytes.size()));
         }
         else if (type_string == RealmObjectTypesDate) {
             return jsc::Object::create_date(m_context, value.get<double>());