From ae6334f358bf3886e3bf4148175ac9055df68696 Mon Sep 17 00:00:00 2001
From: Mathieu David <mathieudavid@mathieudavid.org>
Date: Wed, 30 Dec 2015 17:19:43 +0100
Subject: [PATCH] Fix bug where we would not check if there was actually a page
 to navigate to when using arrow keys

---
 src/theme/book.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/theme/book.js b/src/theme/book.js
index 89f71c45..9724d044 100644
--- a/src/theme/book.js
+++ b/src/theme/book.js
@@ -32,11 +32,15 @@ $( document ).ready(function() {
         switch (e.keyCode) {
             case KEY_CODES.NEXT_KEY:
                 e.preventDefault();
-                window.location.href = $('.nav-chapters.next').attr('href');
+                if($('.nav-chapters.next').length) {
+                    window.location.href = $('.nav-chapters.next').attr('href');
+                }
                 break;
             case KEY_CODES.PREVIOUS_KEY:
                 e.preventDefault();
-                window.location.href = $('.nav-chapters.previous').attr('href');
+                if($('.nav-chapters.previous').length) {
+                    window.location.href = $('.nav-chapters.previous').attr('href');
+                }
                 break;
         }
     });