fix(b-form-tags): improve accessibility for screen reader users (#4775)

* fix(b-form-tag): improve accessibility of individual tags

* Update form-tag.js

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update config-defaults.js

* Update package.json

* Update form-tags.js

* Update package.json

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update form-tags.js

* Update form-tag.js

* Update form-tag.js

* Update form-tag.js

* Update form-tag.js

* Update form-tags.js

* Update form-tag.js

* Update form-tags.js

* Update form-tags.js

* Update README.md

* Update form-tags.js

* Update README.md

* Update package.json

* Update form-tags.js

* Update README.md

* Prettify

* Update README.md

* Update README.md

Co-authored-by: Jacob Müller <jacob.mueller.elz@gmail.com>

src/components/button/README.md

@@ -260,12 +260,12 @@ Note the `<router-link>` prop `tag` is referred to as `router-tag` in `bootstrap
 ## Accessibility
 
 When the `href` prop is set to `'#'`, `<b-button>` will render a link (`<a>`) element with attribute
-`role="button"` set and apropriate keydown listeners (<kbd>Enter</kbd> and <kbd>Space</kbd>) so that
-the link acts like a native HTML `<button>` for screen reader and keyboard-only users. When disabled,
-the `aria-disabled="true"` attribute will be set on the `<a>` element.
+`role="button"` set and appropriate keydown listeners (<kbd>Enter</kbd> and <kbd>Space</kbd>) so
+that the link acts like a native HTML `<button>` for screen reader and keyboard-only users. When
+disabled, the `aria-disabled="true"` attribute will be set on the `<a>` element.
 
 When the `href` is set to any other value (or the `to` prop is used), `role="button"` will not be
-added, nor will the keyboad event listeners be enabled.
+added, nor will the keyboard event listeners be enabled.
 
 ## See also
 

src/components/form-tags/README.md

@@ -22,7 +22,8 @@ button will only appear when the user has entered a new tag value.
 ```html
 <template>
   <div>
-    <b-form-tags v-model="value" class="mb-2"></b-form-tags>
+    <label for="tags-basic">Type a new tag and press enter</label>
+    <b-form-tags input-id="tags-basic" v-model="value" class="mb-2"></b-form-tags>
     <p>Value: {{ value }}</p>
   </div>
 </template>
@@ -57,7 +58,9 @@ are typed:
 ```html
 <template>
   <div>
+    <label for="tags-separators">Enter tags separated by space, comma or semicolon</label>
     <b-form-tags
+      input-id="tags-separators"
       v-model="value"
       separator=" ,;"
       placeholder="Enter new tags separated by space, comma or semicolon"
@@ -81,22 +84,28 @@ are typed:
 <!-- form-tags-separator.vue -->
 ```
 
-## Last tag removal via delete keypress
+## Last tag removal via backspace keypress
 
-When the prop `remove-on-delete` is set, and the user presses <kbd>DEL</kbd> _and_ the input value
-is empty, the last tag in the tag list will be removed.
+When the prop `remove-on-delete` is set, and the user presses <kbd>BACKSPACE</kbd> (or
+<kbd>DEL</kbd>) _and_ the input value is empty, the last tag in the tag list will be removed.
 
 ```html
 <template>
   <div>
+    <label for="tags-remove-on-delete">Enter new tags separated by space</label>
     <b-form-tags
+      input-id="tags-remove-on-delete"
+      :input-attrs="{ 'aria-describedby': 'tags-remove-on-delete-help' }"
       v-model="value"
       separator=" "
       placeholder="Enter new tags separated by space"
       remove-on-delete
       no-add-on-enter
       class="mb-2"
     ></b-form-tags>
+    <b-form-text id="tags-remove-on-delete-help">
+      Press <kbd>BACKSPACE</kbd> to remove the last tag entered
+    </b-form-text>
     <p>Value: {{ value }}</p>
   </div>
 </template>
@@ -134,7 +143,9 @@ The focus and validation state styling of the component relies upon BootstrapVue
 ```html
 <template>
   <div>
+    <label for="tags-pills">Enter tags</label>
     <b-form-tags
+      input-id="tags-pills"
       v-model="value"
       tag-variant="primary"
       tag-pills
@@ -186,8 +197,10 @@ not validated.
 ```html
 <template>
   <div>
-    <b-form-group :state="state" label="Tags validation example">
+    <b-form-group :state="state" label="Tags validation example" label-for="tags-validation">
       <b-form-tags
+        input-id="tags-validation"
+        :input-attrs="{ 'aria-describedby': 'tags-validation-help' }"
         v-model="tags"
         :state="state"
         :tag-validator="tagValidator"
@@ -198,8 +211,10 @@ not validated.
         You must provide at least 3 tags and no more than 8
       </template>
       <template v-slot:description>
-        Tags must be 3 to 5 characters in length and all lower
-        case. Enter tags separated by spaces or press enter.
+        <div id="tags-validation-help">
+         Tags must be 3 to 5 characters in length and all lower
+         case. Enter tags separated by spaces or press enter.
+        </div>
       </template>
     </b-form-group>
   </div>
@@ -260,7 +275,9 @@ to either an empty string (`''`) or `null`.
 ```html
 <template>
   <div>
+    <label for="tags-state-event">Enter tags</label>
     <b-form-tags
+      input-id="tags-state-event"
       v-model="tags"
       :tag-validator="validator"
       placeholder="Enter tags (3-5 characters) separated by space"

src/components/form-tags/form-tag.js

@@ -1,4 +1,5 @@
 import Vue from '../../utils/vue'
+import KeyCodes from '../../utils/key-codes'
 import { getComponentConfig } from '../../utils/config'
 import idMixin from '../../mixins/id'
 import normalizeSlotMixin from '../../mixins/normalize-slot'
@@ -37,32 +38,49 @@ export const BFormTag = /*#__PURE__*/ Vue.extend({
     }
   },
   methods: {
-    onClick() {
-      this.$emit('remove')
+    onDelete(evt) {
+      const { type, keyCode } = evt
+      if (
+        !this.disabled &&
+        (type === 'click' || (type === 'keydown' && keyCode === KeyCodes.DELETE))
+      ) {
+        this.$emit('remove')
+      }
     }
   },
   render(h) {
     const tagId = this.safeId()
+    const tagLabelId = this.safeId('_taglabel_')
     let $remove = h()
     if (!this.disabled) {
       $remove = h(BButtonClose, {
         staticClass: 'b-form-tag-remove ml-1',
         props: { ariaLabel: this.removeLabel },
-        attrs: { 'aria-controls': tagId },
-        on: { click: this.onClick }
+        attrs: {
+          'aria-controls': tagId,
+          'aria-describedby': tagLabelId,
+          'aria-keyshortcuts': 'Delete'
+        },
+        on: {
+          click: this.onDelete,
+          keydown: this.onDelete
+        }
       })
     }
     const $tag = h(
       'span',
-      { staticClass: 'b-form-tag-content flex-grow-1 text-truncate' },
+      {
+        staticClass: 'b-form-tag-content flex-grow-1 text-truncate',
+        attrs: { id: tagLabelId }
+      },
       this.normalizeSlot('default') || this.title || [h()]
     )
     return h(
       BBadge,
       {
         staticClass: 'b-form-tag d-inline-flex align-items-baseline mw-100',
         class: { disabled: this.disabled },
-        attrs: { id: tagId, title: this.title || null },
+        attrs: { id: tagId, title: this.title || null, 'aria-labelledby': tagLabelId },
         props: { tag: this.tag, variant: this.variant, pill: this.pill }
       },
       [$tag, $remove]

src/components/form-tags/form-tags.js

@@ -1,8 +1,8 @@
 // Tagged input form control
 // Based loosely on https://adamwathan.me/renderless-components-in-vuejs/
 import Vue from '../../utils/vue'
-import identity from '../../utils/identity'
 import KeyCodes from '../../utils/key-codes'
+import identity from '../../utils/identity'
 import looseEqual from '../../utils/loose-equal'
 import { arrayIncludes, concat } from '../../utils/array'
 import { getComponentConfig } from '../../utils/config'
@@ -11,10 +11,10 @@ import { isEvent, isFunction, isString } from '../../utils/inspect'
 import { escapeRegExp, toString, trim, trimLeft } from '../../utils/string'
 import idMixin from '../../mixins/id'
 import normalizeSlotMixin from '../../mixins/normalize-slot'
-import { BFormTag } from './form-tag'
+import { BButton } from '../button/button'
 import { BFormInvalidFeedback } from '../form/form-invalid-feedback'
 import { BFormText } from '../form/form-text'
-import { BButton } from '../button/button'
+import { BFormTag } from './form-tag'
 
 // --- Constants ---
 
@@ -26,6 +26,9 @@ const TYPES = ['text', 'email', 'tel', 'url', 'number']
 // Pre-compiled regular expressions for performance reasons
 const RX_SPACES = /[\s\uFEFF\xA0]+/g
 
+// KeyCode constants
+const { ENTER, BACKSPACE, DELETE } = KeyCodes
+
 // --- Utility methods ---
 
 // Escape special chars in string and replace
@@ -132,6 +135,10 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
       type: String,
       default: () => getComponentConfig(NAME, 'tagRemoveLabel')
     },
+    tagRemovedLabel: {
+      type: String,
+      default: () => getComponentConfig(NAME, 'tagRemovedLabel')
+    },
     tagValidator: {
       type: Function,
       default: null
@@ -182,6 +189,8 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
       hasFocus: false,
       newTag: '',
       tags: [],
+      // Tags that were removed
+      removedTags: [],
       // Populated when tags are parsed
       tagsState: cleanTagsState()
     }
@@ -263,11 +272,16 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
     value(newVal) {
       this.tags = cleanTags(newVal)
     },
-    tags(newVal) {
+    tags(newVal, oldVal) {
       // Update the `v-model` (if it differs from the value prop)
       if (!looseEqual(newVal, this.value)) {
         this.$emit('input', newVal)
       }
+      if (!looseEqual(newVal, oldVal)) {
+        newVal = concat(newVal).filter(identity)
+        oldVal = concat(oldVal).filter(identity)
+        this.removedTags = oldVal.filter(old => !arrayIncludes(newVal, old))
+      }
     },
     tagsState(newVal, oldVal) {
       // Emit a tag-state event when the `tagsState` object changes
@@ -336,7 +350,9 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
       //   Or emit cancelable `BvEvent`
       this.tags = this.tags.filter(t => t !== tag)
       // Return focus to the input (if possible)
-      this.focus()
+      this.$nextTick(() => {
+        this.focus()
+      })
     },
     // --- Input element event handlers ---
     onInputInput(evt) {
@@ -383,20 +399,26 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
       const keyCode = evt.keyCode
       const value = evt.target.value || ''
       /* istanbul ignore else: testing to be added later */
-      if (!this.noAddOnEnter && keyCode === KeyCodes.ENTER) {
+      if (!this.noAddOnEnter && keyCode === ENTER) {
         // Attempt to add the tag when user presses enter
         evt.preventDefault()
         this.addTag()
-      } else if (this.removeOnDelete && keyCode === KeyCodes.BACKSPACE && value === '') {
-        // Remove the last tag if the user pressed backspace and the input is empty
+      } else if (
+        this.removeOnDelete &&
+        (keyCode === BACKSPACE || keyCode === DELETE) &&
+        value === ''
+      ) {
+        // Remove the last tag if the user pressed backspace/delete and the input is empty
         evt.preventDefault()
-        this.tags.pop()
+        this.tags = this.tags.slice(0, -1)
       }
     },
     // --- Wrapper event handlers ---
     onClick(evt) {
       if (!this.disabled && isEvent(evt) && evt.target === evt.currentTarget) {
-        this.$nextTick(this.focus)
+        this.$nextTick(() => {
+          this.focus()
+        })
       }
     },
     onFocusin() {
@@ -512,7 +534,7 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
             staticClass: 'mt-1 mr-1',
             class: tagClass,
             props: {
-              // 'BFormTag' will auto generate an ID
+              // `BFormTag` will auto generate an ID
               // so we do not need to set the ID prop
               tag: 'li',
               title: tag,
@@ -591,10 +613,14 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
         'li',
         {
           key: '__li-input__',
-          staticClass: 'd-inline-flex flex-grow-1 mt-1',
-          attrs: { role: 'group', 'aria-live': 'off', 'aria-controls': tagListId }
+          staticClass: 'flex-grow-1 mt-1',
+          attrs: {
+            role: 'none',
+            'aria-live': 'off',
+            'aria-controls': tagListId
+          }
         },
-        [$input, $button]
+        [h('div', { staticClass: 'd-flex', attrs: { role: 'group' } }, [$input, $button])]
       )
 
       // Wrap in an unordered list element (we use a list for accessibility)
@@ -603,16 +629,7 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
         {
           key: '_tags_list_',
           staticClass: 'list-unstyled mt-n1 mb-0 d-flex flex-wrap align-items-center',
-          attrs: {
-            id: tagListId,
-            // Don't interrupt the user abruptly
-            // Although maybe this should be 'assertive'
-            // to provide immediate feedback of the tag added/removed
-            'aria-live': 'polite',
-            // Only read elements that have been added or removed
-            'aria-atomic': 'false',
-            'aria-relevant': 'additions removals'
-          }
+          attrs: { id: tagListId }
         },
         // `concat()` is faster than array spread when args are known to be arrays
         concat($tags, $field)
@@ -707,6 +724,38 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
     // Generate the user interface
     const $content = this.normalizeSlot('default', scope) || this.defaultRender(scope)
 
+    // Generate the `aria-live` region for the current value(s)
+    const $output = h(
+      'output',
+      {
+        staticClass: 'sr-only',
+        attrs: {
+          id: this.safeId('_selected-tags_'),
+          role: 'status',
+          for: this.computedInputId,
+          'aria-live': this.hasFocus ? 'polite' : 'off',
+          'aria-atomic': 'true',
+          'aria-relevant': 'additions text'
+        }
+      },
+      this.tags.join(', ')
+    )
+
+    // Removed tag live region
+    const $removed = h(
+      'div',
+      {
+        staticClass: 'sr-only',
+        attrs: {
+          id: this.safeId('_removed-tags_'),
+          role: 'status',
+          'aria-live': this.hasFocus ? 'assertive' : 'off',
+          'aria-atomic': 'true'
+        }
+      },
+      this.removedTags.length > 0 ? `(${this.tagRemovedLabel}) ${this.removedTags.join(', ')}` : ''
+    )
+
     // Add hidden inputs for form submission
     let $hidden = h()
     if (this.name && !this.disabled) {
@@ -740,15 +789,16 @@ export const BFormTags = /*#__PURE__*/ Vue.extend({
         attrs: {
           id: this.safeId(),
           role: 'group',
-          tabindex: this.disabled || this.noOuterFocus ? null : '-1'
+          tabindex: this.disabled || this.noOuterFocus ? null : '-1',
+          'aria-describedby': this.safeId('_selected_')
         },
         on: {
           focusin: this.onFocusin,
           focusout: this.onFocusout,
           click: this.onClick
         }
       },
-      concat($content, $hidden)
+      concat($output, $removed, $content, $hidden)
     )
   }
 })