Make query bar autocomplete screen reader accessible (#20740)

Fixes #20099

I made the changes described by Tim at #20099 and everything seems to be working. I tried to update the typeahead in such a way that it can be made accessible anywhere it is used, even if there are multiple typeahead instances on a single page.

> (optional) an aria-label on the individual suggestions that should be read out to screen reader. By default the content will be used, and that should be fine (unless you figure out there is too much "noise" elements in it.

I did not do this bit since the text that is read seems reasonable to me, but I'm open to changing it if others feel differently.

src/ui/public/query_bar/directive/query_bar.html

@@ -6,7 +6,9 @@
   <kbn-typeahead
     items="queryBar.suggestions"
     item-template="queryBar.suggestionTemplate"
+    id="query-bar-suggestions"
     on-select="queryBar.onSuggestionSelect(item)"
+    on-focus-change="queryBar.focusedTypeaheadItemID = $focusedItemID"
     class="suggestionTypeahead"
   >
     <div
@@ -30,6 +32,10 @@
           class="kuiLocalSearchInput"
           ng-class="{'kuiLocalSearchInput-isInvalid': queryBarForm.$invalid}"
           data-test-subj="queryInput"
+          aria-autocomplete="list"
+          aria-controls="query-bar-suggestions-typeahead-items"
+          aria-activedescendant="{{queryBar.focusedTypeaheadItemID}}"
+          role="textbox"
         >
 
         <!-- kuery input -->
@@ -51,6 +57,10 @@
           class="kuiLocalSearchInput"
           ng-class="{'kuiLocalSearchInput-isInvalid': queryBarForm.$invalid}"
           data-test-subj="queryInput"
+          aria-autocomplete="list"
+          aria-controls="query-bar-suggestions-typeahead-items"
+          aria-activedescendant="{{queryBar.focusedTypeaheadItemID}}"
+          role="textbox"
         />
         <div class="kuiLocalSearchAssistedInput__assistance">
             <query-popover

src/ui/public/query_bar/directive/query_bar.js

@@ -47,6 +47,7 @@ module.directive('queryBar', function () {
 
     controller: callAfterBindingsWorkaround(function ($scope, $element, $http, $timeout, config, PersistedLog, indexPatterns) {
       this.appName = this.appName || 'global';
+      this.focusedTypeaheadItemID = '';
 
       this.getIndexPatterns = () => {
         if (compact(this.indexPatterns).length) return Promise.resolve(this.indexPatterns);

src/ui/public/query_bar/directive/suggestion.html

@@ -1,19 +1,19 @@
 <div class="suggestionItem suggestionItem--{{item.type}}">
   <div class="suggestionItem__type">
     <div ng-switch="item.type">
-      <div ng-switch-when="field">
+      <div ng-switch-when="field" aria-label="Field">
         <icon type="'kqlField'"></icon>
       </div>
-      <div ng-switch-when="value">
+      <div ng-switch-when="value" aria-label="Value">
         <icon type="'kqlValue'"></icon>
       </div>
-      <div ng-switch-when="recentSearch">
+      <div ng-switch-when="recentSearch" aria-label="Recent search">
         <icon type="'search'"></icon>
       </div>
-      <div ng-switch-when="conjunction">
+      <div ng-switch-when="conjunction" aria-label="Conjunction">
         <icon type="'kqlSelector'"></icon>
       </div>
-      <div ng-switch-when="operator">
+      <div ng-switch-when="operator" aria-label="Operator">
         <icon type="'kqlOperand'"></icon>
       </div>
     </div>

src/ui/public/typeahead/typeahead.html

@@ -2,6 +2,10 @@
   class="typeahead"
   ng-keydown="typeahead.onKeyDown($event)"
   ng-keypress="typeahead.onKeyPress($event)"
+  role="combobox"
+  aria-haspopup="true"
+  aria-owns="{{typeahead.elementID}}-typeahead-items"
+  aria-expanded="{{typeahead.isVisible() ? true : false}}"
 >
   <ng-transclude></ng-transclude>
   <div
@@ -13,13 +17,17 @@
     <div
       class="typeahead-items"
       kbn-scroll-bottom="typeahead.increaseLimit()"
+      role="listbox"
+      id="{{typeahead.elementID}}-typeahead-items"
     >
       <div
         class="typeahead-item"
         ng-repeat="item in typeahead.items | limitTo: typeahead.limit"
         ng-class="{active: $index === typeahead.selectedIndex}"
         ng-click="typeahead.onItemClick()"
         ng-mouseenter="typeahead.selectedIndex = $index"
+        role="option"
+        id="{{typeahead.elementID}}-typeahead-item-{{$index}}"
       >
         <kbn-typeahead-item
           item="item"

src/ui/public/typeahead/typeahead.js

@@ -36,13 +36,15 @@ typeahead.directive('kbnTypeahead', function () {
     scope: {
       items: '=',
       itemTemplate: '=',
-      onSelect: '&'
+      onSelect: '&',
+      onFocusChange: '&'
     },
     bindToController: true,
     controllerAs: 'typeahead',
     controller: function ($scope, $element) {
       this.isHidden = true;
       this.selectedIndex = null;
+      this.elementID = $element.attr('id');
 
       this.submit = () => {
         const item = this.items[this.selectedIndex];
@@ -137,6 +139,10 @@ typeahead.directive('kbnTypeahead', function () {
       this.onMouseLeave = () => {
         this.isMousedOver = false;
       };
+
+      $scope.$watch('typeahead.selectedIndex', (newIndex) => {
+        this.onFocusChange({ $focusedItemID: newIndex !== null ? `${this.elementID}-typeahead-item-${newIndex}` : '' });
+      });
     }
   };
 });