diff --git a/lib/mem-store.js b/lib/mem-store.js
index 0dc8f6b..3dec72b 100644
--- a/lib/mem-store.js
+++ b/lib/mem-store.js
@@ -4,14 +4,7 @@
  * @date 2020/09/18 16:35:26
  */
 
-function hideProperty(host, name, value) {
-  Object.defineProperty(host, name, {
-    value: value,
-    writable: true,
-    enumerable: false,
-    configurable: true
-  })
-}
+import fs from 'fs'
 
 export default class Session {
   constructor(opt) {
@@ -33,7 +26,7 @@ export default class Session {
     }
 
     // 设置session有效期
-    hideProperty(session, '__expires__', Date.now() + this.ttl * 1000)
+    session.__expires__ = Date.now() + this.ttl * 1000
   }
 
   // 获取session字段值