feat(ByRole): Allow filter by selected state (#540)

Author: eps1lon

src/__tests__/ariaAttributes.js

@@ -0,0 +1,85 @@
+import {render} from './helpers/test-utils'
+
+test('`selected` throws on unsupported roles', () => {
+  const {getByRole} = render(`<input aria-selected="true" type="text">`)
+  expect(() =>
+    getByRole('textbox', {selected: true}),
+  ).toThrowErrorMatchingInlineSnapshot(
+    `"\\"aria-selected\\" is not supported on role \\"textbox\\"."`,
+  )
+})
+
+test('`selected: true` matches `aria-selected="true"` on supported roles', () => {
+  const {getAllByRole} = render(`
+<select>
+  <option selected id="selected-native-option" />
+  <option id="unselected-native-option" />
+</select>
+<div role="listbox">
+  <div role="option" aria-selected="true" id="selected-listbox-option" />
+  <div role="option" aria-selected="false" id="unselected-listbox-option" />
+  <div role="option" id="not-selectable-listbox-option" />
+</div>
+<div role="tree">
+  <div role="treeitem" aria-selected="true" id="selected-treeitem" />
+  <div role="treeitem" aria-selected="false" id="unselected-treeitem" />
+  <div role="treeitem" id="not-selectable-treeitem" />
+</div>
+<table>
+  <thead>
+    <tr>
+      <th scope="col" aria-selected="true" id="selected-native-columnheader" />
+      <div role="columnheader" aria-selected="true" id="selected-columnheader" />
+      <th scope="col" id="unselected-native-columnheader" />
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <th scope="row" aria-selected="true" id="selected-native-rowheader" />
+      <td />
+      <td />
+    </tr>
+    <tr>
+      <div role="rowheader" aria-selected="true" id="selected-rowheader" />
+      <td />
+      <td />
+    </tr>
+  </tbody>
+</table>
+<div role="grid">
+  <div role="gridcell" aria-selected="true" id="selected-gridcell" />
+  <div role="gridcell" aria-selected="false" id="unselected-gridcell" />
+  <div role="gridcell" id="not-selectable-gridcell" />
+</div>
+<div role="tablist">
+  <div role="tab" aria-selected="true" id="selected-tab" />
+  <div role="tab" aria-selected="false" id= "unselected-tab" />
+  <div role="tab" id="unselectable-tab" />
+</div>
+`)
+
+  expect(
+    getAllByRole('columnheader', {selected: true}).map(({id}) => id),
+  ).toEqual(['selected-native-columnheader', 'selected-columnheader'])
+
+  expect(getAllByRole('gridcell', {selected: true}).map(({id}) => id)).toEqual([
+    'selected-gridcell',
+  ])
+
+  expect(getAllByRole('option', {selected: true}).map(({id}) => id)).toEqual([
+    'selected-native-option',
+    'selected-listbox-option',
+  ])
+
+  expect(
+    getAllByRole('rowheader', {selected: true}).map(({id}) => id),
+  ).toEqual(['selected-rowheader', 'selected-native-rowheader'])
+
+  expect(getAllByRole('treeitem', {selected: true}).map(({id}) => id)).toEqual([
+    'selected-treeitem',
+  ])
+
+  expect(getAllByRole('tab', {selected: true}).map(({id}) => id)).toEqual([
+    'selected-tab',
+  ])
+})

src/queries/role.js

@@ -1,5 +1,7 @@
 import {computeAccessibleName} from 'dom-accessibility-api'
+import {roles as allRoles} from 'aria-query'
 import {
+  computeAriaSelected,
   getImplicitAriaRoles,
   prettyRoles,
   isInaccessible,
@@ -24,11 +26,19 @@ function queryAllByRole(
     trim,
     normalizer,
     queryFallbacks = false,
+    selected,
   } = {},
 ) {
   const matcher = exact ? matches : fuzzyMatches
   const matchNormalizer = makeNormalizer({collapseWhitespace, trim, normalizer})
 
+  if (selected !== undefined) {
+    // guard against unknown roles
+    if (allRoles.get(role)?.props['aria-selected'] === undefined) {
+      throw new Error(`"aria-selected" is not supported on role "${role}".`)
+    }
+  }
+
   const subtreeIsInaccessibleCache = new WeakMap()
   function cachedIsSubtreeInaccessible(element) {
     if (!subtreeIsInaccessibleCache.has(element)) {
@@ -65,6 +75,13 @@ function queryAllByRole(
         matcher(implicitRole, node, role, matchNormalizer),
       )
     })
+    .filter(element => {
+      if (selected !== undefined) {
+        return selected === computeAriaSelected(element)
+      }
+      // don't care if aria attributes are unspecified
+      return true
+    })
     .filter(element => {
       return hidden === false
         ? isInaccessible(element, {

src/role-helpers.js

@@ -168,11 +168,33 @@ function prettyRoles(dom, {hidden}) {
 const logRoles = (dom, {hidden = false} = {}) =>
   console.log(prettyRoles(dom, {hidden}))
 
+/**
+ * @param {Element} element -
+ * @returns {boolean | undefined} - false/true if (not)selected, undefined if not selectable
+ */
+function computeAriaSelected(element) {
+  // implicit value from html-aam mappings: https://www.w3.org/TR/html-aam-1.0/#html-attribute-state-and-property-mappings
+  // https://www.w3.org/TR/html-aam-1.0/#details-id-97
+  if (element.tagName === 'OPTION') {
+    return element.selected
+  }
+  // explicit value
+  const attributeValue = element.getAttribute('aria-selected')
+  if (attributeValue === 'true') {
+    return true
+  }
+  if (attributeValue === 'false') {
+    return false
+  }
+  return undefined
+}
+
 export {
   getRoles,
   logRoles,
   getImplicitAriaRoles,
   isSubtreeInaccessible,
   prettyRoles,
   isInaccessible,
+  computeAriaSelected,
 }