diff --git a/src/reactivity/__tests__/reactive.spec.ts b/src/reactivity/__tests__/reactive.spec.ts
index 1b4c705..0e8caf3 100644
--- a/src/reactivity/__tests__/reactive.spec.ts
+++ b/src/reactivity/__tests__/reactive.spec.ts
@@ -6,6 +6,12 @@ describe("reactive", () => {
     expect(observed).not.toBe(original);
     expect(isReactive(observed)).toBe(true);
     expect(isReactive(original)).toBe(false);
+    // hack
+    const evil = {
+      __v_isReactive: true,
+      __v_isReadonly: true,
+    }
+    expect(isReactive(evil)).toBe(false)
     // get
     expect(observed.foo).toBe(1);
     //     // has
diff --git a/src/reactivity/__tests__/readonly.spec.ts b/src/reactivity/__tests__/readonly.spec.ts
index 06da20c..8848b48 100644
--- a/src/reactivity/__tests__/readonly.spec.ts
+++ b/src/reactivity/__tests__/readonly.spec.ts
@@ -14,6 +14,12 @@ describe("readonly", () => {
     expect(isReadonly(wrapped.bar)).toBe(true);
     expect(isReactive(original.bar)).toBe(false);
     expect(isReadonly(original.bar)).toBe(false);
+    // hack
+    const evil = {
+      __v_isReactive: true,
+      __v_isReadonly: true,
+    }
+    expect(isReadonly(evil)).toBe(false)
     // get
     expect(wrapped.foo).toBe(1);
   });
diff --git a/src/reactivity/src/reactive.ts b/src/reactivity/src/reactive.ts
index ac87c19..cf24b8b 100644
--- a/src/reactivity/src/reactive.ts
+++ b/src/reactivity/src/reactive.ts
@@ -8,11 +8,11 @@ export const reactiveMap = new WeakMap();
 export const readonlyMap = new WeakMap();
 export const shallowReadonlyMap = new WeakMap();
 
-export const enum ReactiveFlags {
-  IS_REACTIVE = "__v_isReactive",
-  IS_READONLY = "__v_isReadonly",
-  RAW = "__v_raw",
-}
+export const ReactiveFlags = {
+  IS_REACTIVE : Symbol("__v_isReactive"),
+  IS_READONLY : Symbol("__v_isReadonly"),
+  RAW : Symbol("__v_raw"),
+} as const
 
 export function reactive(target) {
   return createReactiveObject(target, reactiveMap, mutableHandlers);