From 21dc56ebf13eddefdcdfd731d5ce1013566d57c5 Mon Sep 17 00:00:00 2001
From: Miro Yovchev <2827783+myovchev@users.noreply.github.com>
Date: Tue, 3 Dec 2024 15:30:08 +0200
Subject: [PATCH] PRO-4431: Context menu dynamic focus trap [a11y] (#4815)

---
 CHANGELOG.md                                          |  5 +++++
 .../ui/ui/apos/components/AposContextMenu.vue         | 11 ++++++++++-
 .../ui/ui/apos/components/AposToggle.vue              |  6 +++++-
 .../ui/ui/apos/composables/AposFocusTrap.js           | 10 ++++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94a6b80207..2b5845787c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,11 @@
 * a11y improvements for context menus.
 * Fixes broken widget preview URL when the image is overridden (module improve) and external build module is registered.
 
+### Adds
+
+* Adds support for dynamic focus trap in Context menus (prop `dynamicFocus`). When set to `true`, the focusable elements are recalculated on each cycle step.
+* Adds option to disable `tabindex` on `AposToggle` component. A new prop `disableFocus` can be set to `false` to disable the focus on the toggle button. It's enabled by default.
+
 ## 4.10.0 (2024-11-20)
 
 ### Fixes
diff --git a/modules/@apostrophecms/ui/ui/apos/components/AposContextMenu.vue b/modules/@apostrophecms/ui/ui/apos/components/AposContextMenu.vue
index c2e072e2d3..a35c8a6b48 100644
--- a/modules/@apostrophecms/ui/ui/apos/components/AposContextMenu.vue
+++ b/modules/@apostrophecms/ui/ui/apos/components/AposContextMenu.vue
@@ -133,6 +133,14 @@ const props = defineProps({
   trapFocus: {
     type: Boolean,
     default: true
+  },
+  // When set to true, the elements to focus on will be re-queried
+  // on everu Tab key press. Use this with caution, as it's a performance
+  // hit. Only use this if you have a context menu with
+  // dynamically changing (e.g. AposToggle item enables another item) items.
+  dynamicFocus: {
+    type: Boolean,
+    default: false
   }
 });
 
@@ -159,7 +167,8 @@ const otherMenuOpened = ref(false);
 const {
   onTab, runTrap, hasRunningTrap, resetTrap
 } = useFocusTrap({
-  withPriority: true
+  withPriority: true,
+  refreshOnCycle: props.dynamicFocus
   // If enabled, the dropdown gets closed when the focus leaves
   // the context menu.
   // triggerRef: dropdownButton,
diff --git a/modules/@apostrophecms/ui/ui/apos/components/AposToggle.vue b/modules/@apostrophecms/ui/ui/apos/components/AposToggle.vue
index ddbc27a0f4..0ca746c508 100644
--- a/modules/@apostrophecms/ui/ui/apos/components/AposToggle.vue
+++ b/modules/@apostrophecms/ui/ui/apos/components/AposToggle.vue
@@ -2,7 +2,7 @@
   <div class="apos-toggle__container">
     <div
       class="apos-toggle__slider"
-      tabindex="0"
+      :tabindex="disableFocus ? null : '0'"
       :class="{'apos-toggle__slider--activated': !modelValue}"
       @click="$emit('toggle')"
       @keydown.stop.space="$emit('toggle')"
@@ -18,6 +18,10 @@ export default {
     modelValue: {
       type: Boolean,
       required: true
+    },
+    disableFocus: {
+      type: Boolean,
+      default: false
     }
   },
   emits: [ 'toggle' ],
diff --git a/modules/@apostrophecms/ui/ui/apos/composables/AposFocusTrap.js b/modules/@apostrophecms/ui/ui/apos/composables/AposFocusTrap.js
index 10f7877a42..b0ed9e385a 100644
--- a/modules/@apostrophecms/ui/ui/apos/composables/AposFocusTrap.js
+++ b/modules/@apostrophecms/ui/ui/apos/composables/AposFocusTrap.js
@@ -9,6 +9,8 @@ import {
  * Options:
  * - `retries`: Number of retries to focus (trap) the first element in the given
  *   container. Default is 3.
+ * - `refreshOnCycle`: If true, the elements to focus will be refreshed (query)
+ *   on each cycle. Default is false.
  * - `withPriority`: If true, 'data-apos-focus-priority' attribute will be used
  *   to find the first element to focus. Default is true.
  * - `triggerRef`: (optional) A ref to the element that will trigger the focus trap.
@@ -18,6 +20,7 @@ import {
  *
  * @param {{
  *  retries?: number;
+ *  refreshOnCycle?: boolean;
  *  withPriority?: boolean;
  *  triggerRef?: import('vue').Ref<HTMLElement | import('vue').ComponentPublicInstance>
  *    | HTMLElement | boolean;
@@ -33,6 +36,7 @@ import {
  */
 export function useFocusTrap({
   triggerRef,
+  refreshOnCycle = false,
   onExit = () => {},
   retries = 3,
   withPriority = true
@@ -47,6 +51,7 @@ export function useFocusTrap({
   const shouldRun = ref(false);
   const isRunning = ref(false);
   const currentRetries = ref(0);
+  const rootRef = ref(null);
   const elementsToFocus = ref([]);
   const hasRunningTrap = computed(() => {
     return isRunning.value;
@@ -113,6 +118,7 @@ export function useFocusTrap({
     if (shouldRun.value) {
       focusElement(findChecked(firstElementToFocus, elements));
       elementsToFocus.value = elements;
+      rootRef.value = unref(containerRef);
     }
   }
 
@@ -154,6 +160,10 @@ export function useFocusTrap({
    * @param {KeyboardEvent} event
    */
   function cycle(event) {
+    if (refreshOnCycle && rootRef.value) {
+      const elements = [ ...unref(rootRef).querySelectorAll(selector) ];
+      elementsToFocus.value = elements;
+    }
     const elements = unref(elementsToFocus);
     parentCycleElementsToFocus(event, elements, focus);