diff --git a/lib/dingtalk-session-ticket.ts b/lib/dingtalk-session-ticket.ts
index 5105cb54..c7cdaae1 100644
--- a/lib/dingtalk-session-ticket.ts
+++ b/lib/dingtalk-session-ticket.ts
@@ -12,11 +12,11 @@ const tickets = new Map<string, DingtalkSessionTicket>()
 
 function cleanupExpiredTickets() {
   const now = Date.now()
-  for (const [id, ticket] of tickets.entries()) {
+  tickets.forEach((ticket, id) => {
     if (ticket.expiresAt <= now) {
       tickets.delete(id)
     }
-  }
+  })
 }
 
 export function createDingtalkSessionTicket(input: {