diff --git a/js/src/jstypedarray.cpp b/js/src/jstypedarray.cpp
index 04b72291d31..6627a406c5f 100644
--- a/js/src/jstypedarray.cpp
+++ b/js/src/jstypedarray.cpp
@@ -2937,6 +2937,7 @@ IMPL_TYPED_ARRAY_JSAPI_CONSTRUCTORS(Float64, double)
     #_typedArray,                                                              \
     JSCLASS_HAS_RESERVED_SLOTS(TypedArray::FIELD_MAX) |                        \
     JSCLASS_HAS_PRIVATE | JSCLASS_IMPLEMENTS_BARRIERS |                        \
+    JSCLASS_HAS_CACHED_PROTO(JSProto_##_typedArray) |                          \
     JSCLASS_FOR_OF_ITERATION |                                                 \
     Class::NON_NATIVE,                                                         \
     JS_PropertyStub,         /* addProperty */                                 \