From 114748b876a2b50b92c3bb30d102dd43dfee42e9 Mon Sep 17 00:00:00 2001
From: Oleksii Trekhleb <trehleb@gmail.com>
Date: Thu, 24 May 2018 09:10:48 +0300
Subject: [PATCH] Refactor peek function in Stack.

---
 src/data-structures/stack/Stack.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/data-structures/stack/Stack.js b/src/data-structures/stack/Stack.js
index daa5d939..664df053 100644
--- a/src/data-structures/stack/Stack.js
+++ b/src/data-structures/stack/Stack.js
@@ -16,7 +16,7 @@ export default class Stack {
    * @return {*}
    */
   peek() {
-    if (!this.linkedList.tail) {
+    if (this.isEmpty()) {
       return null;
     }