Hide the sidebar when collapsed to prevent browser search to find text from it

Author: GuillaumeGomez

src/front-end/css/chrome.css

@@ -530,7 +530,6 @@ html:not(.sidebar-resizing) .sidebar {
 /* sidebar-hidden */
 #sidebar-toggle-anchor:not(:checked) ~ .sidebar {
     transform: translateX(calc(0px - var(--sidebar-width) - var(--sidebar-resize-indicator-width)));
-    z-index: -1;
 }
 [dir=rtl] #sidebar-toggle-anchor:not(:checked) ~ .sidebar {
     transform: translateX(calc(var(--sidebar-width) + var(--sidebar-resize-indicator-width)));

src/front-end/js/book.js

@@ -521,8 +521,25 @@ aria-label="Show hidden lines"></button>';
     const sidebarToggleButton = document.getElementById('sidebar-toggle');
     const sidebarToggleAnchor = document.getElementById('sidebar-toggle-anchor');
     const sidebarResizeHandle = document.getElementById('sidebar-resize-handle');
+    const sidebarCheckbox = document.getElementById('sidebar-toggle-anchor');
     let firstContact = null;
 
+    /* Because we cannot change the `display` using only CSS after/before the transition, we
+       need JS to do it. We change the display to prevent the browsers search to find text inside
+       the collapsed sidebar. */
+    sidebar.addEventListener('transitionend', () => {
+        /* We only change the display to "none" if we're collapsing the sidebar. */
+        if (!sidebarCheckbox.checked) {
+            sidebar.style.display = 'none';
+        }
+    });
+    sidebarToggleButton.addEventListener('click', () => {
+        /* To allow the sidebar expansion animation, we first need to put back the display. */
+        if (!sidebarCheckbox.checked) {
+            sidebar.style.display = '';
+        }
+    });
+
     function showSidebar() {
         body.classList.remove('sidebar-hidden');
         body.classList.add('sidebar-visible');