diff --git a/js-runtime/src/js-runtime.js b/js-runtime/src/js-runtime.js
index 4572a137..5524b78f 100644
--- a/js-runtime/src/js-runtime.js
+++ b/js-runtime/src/js-runtime.js
@@ -252,6 +252,11 @@ const zig = {
     delete values[id][index];
   },
 
+  zigGetAttributeCount(id) {
+    let obj = values[id];
+    return Object.keys(obj).length;
+  },
+
   zigCleanupObject(id) {
     const idx = Number(id);
     delete value_map[values[idx].__uindex];
diff --git a/js-runtime/src/main.zig b/js-runtime/src/main.zig
index 07b35922..d4efa6b7 100644
--- a/js-runtime/src/main.zig
+++ b/js-runtime/src/main.zig
@@ -7,6 +7,7 @@ const js = struct {
     extern fn zigCreateArray() u32;
     extern fn zigCreateString(str: [*]const u8, len: u32) u32;
     extern fn zigCreateFunction(id: *const anyopaque) u32;
+    extern fn zigGetAttributeCount(id: u64) u32;
     extern fn zigGetProperty(id: u64, name: [*]const u8, len: u32, ret_ptr: *anyopaque) void;
     extern fn zigSetProperty(id: u64, name: [*]const u8, len: u32, set_ptr: *const anyopaque) void;
     extern fn zigDeleteProperty(id: u64, name: [*]const u8, len: u32) void;
@@ -91,6 +92,10 @@ pub const Object = struct {
         return .{ .tag = .object, .val = .{ .ref = obj.ref } };
     }
 
+    pub fn attributeCount(obj: *const Object) usize {
+        return js.zigGetAttributeCount(obj.ref);
+    }
+
     pub fn get(obj: *const Object, prop: []const u8) Value {
         var ret: Value = undefined;
         js.zigGetProperty(obj.ref, prop.ptr, @intCast(u32, prop.len), &ret);