diff --git a/src/io.ts b/src/io.ts
index 6753c4c3981697b67de6998f693c4d594964f9b7..0d28b58fc4a5d3106098660ca4b3058ff4017413 100644
--- a/src/io.ts
+++ b/src/io.ts
@@ -299,7 +299,7 @@ export class Io {
     this.reconnectTimer = setTimeout(_ => {
       this.reconnectTimer = null
       this.initWebSocket()
-    }, this.reconnectTimeout)
+    }, this.reconnectTimeout) as any as NodeJS.Timer
   }
 
   private initEventHook() {