diff --git a/js/modules/k6/data/share.go b/js/modules/k6/data/share.go
index 828726cc38f..2d8345a0234 100644
--- a/js/modules/k6/data/share.go
+++ b/js/modules/k6/data/share.go
@@ -75,7 +75,7 @@ func (s wrappedSharedArray) deepFreeze(rt *goja.Runtime, val goja.Value) error {
 	if o == nil {
 		return nil
 	}
-	for _, key := range o.Keys() {
+	for _, key := range o.Prototype().Keys() {
 		prop := o.Get(key)
 		if prop != nil {
 			// isFrozen returns true for all non objects so it we don't need to check that