Make the arrow keys honor RTL.

At least to my understanding, the pages will flip in the opposite direction.

Author: ehuss

src/theme/book.js

@@ -557,20 +557,35 @@ function playground_text(playground, hidden = true) {
     document.addEventListener('keydown', function (e) {
         if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
         if (window.search && window.search.hasFocus()) { return; }
+        var html = document.querySelector('html');
 
+        function next() {
+            var nextButton = document.querySelector('.nav-chapters.next');
+            if (nextButton) {
+                window.location.href = nextButton.href;
+            }
+        }
+        function prev() {
+            var previousButton = document.querySelector('.nav-chapters.previous');
+            if (previousButton) {
+                window.location.href = previousButton.href;
+            }
+        }
         switch (e.key) {
             case 'ArrowRight':
                 e.preventDefault();
-                var nextButton = document.querySelector('.nav-chapters.next');
-                if (nextButton) {
-                    window.location.href = nextButton.href;
+                if (html.dir == 'rtl') {
+                    prev();
+                } else {
+                    next();
                 }
                 break;
             case 'ArrowLeft':
                 e.preventDefault();
-                var previousButton = document.querySelector('.nav-chapters.previous');
-                if (previousButton) {
-                    window.location.href = previousButton.href;
+                if (html.dir == 'rtl') {
+                    next();
+                } else {
+                    prev();
                 }
                 break;
         }