diff --git a/main.js b/main.js
index 734e17d..a215959 100644
--- a/main.js
+++ b/main.js
@@ -1,7 +1,5 @@
 const setGlobalVar = require("./lib/setCookie");
 
-const isUndefined = value => typeof value === 'undefined';
-
 const {
     SCKEY,
     COOKIE,
@@ -14,7 +12,7 @@ const {
 const COOKIE_ARR = [COOKIE, COOKIE_2, COOKIE_3, COOKIE_4, COOKIE_5];
 
 COOKIE_ARR.forEach((cookie, num) => {
-    if (isUndefined(cookie)) return;
+    if (typeof cookie === 'undefined') return;
     setGlobalVar(cookie, SCKEY).then(async () => {
         const { start, isMe, checkCookie } = require("./lib/lottery-in-nodejs");
         const isRight = await checkCookie(num + 1);