fix(material/chips): add support for aria-description

Add support for aria-description on mat-chip, mat-chip-option and
mat-chip-row. mat-chip-option and mat-chip-row put aria-desciprtion on
the same element that already has the aria-label.

aria-description is needed for when developers need to provide more
information that in the aria-label. This is especially needed for
chip-row when [editable]="true". That's because it gives a way to
communicate to screen reader users how to begin editing a chip.

src/components-examples/material/chips/chips-input/chips-input-example.html

@@ -4,9 +4,10 @@
     <mat-chip-row *ngFor="let fruit of fruits"
                   (removed)="remove(fruit)"
                   [editable]="true"
-                  (edited)="edit(fruit, $event)">
+                  (edited)="edit(fruit, $event)"
+                  [aria-description]="'press enter to edit ' + fruit.name">
       {{fruit.name}}
-      <button matChipRemove [attr.aria-label]="'remove ' + fruit">
+      <button matChipRemove [attr.aria-label]="'remove ' + fruit.name">
         <mat-icon>cancel</mat-icon>
       </button>
     </mat-chip-row>

src/components-examples/material/chips/chips-input/chips-input-example.ts

@@ -50,7 +50,7 @@ export class ChipsInputExample {
 
     // Edit existing fruit
     const index = this.fruits.indexOf(fruit);
-    if (index > 0) {
+    if (index >= 0) {
       this.fruits[index].name = value;
     }
   }

src/material/chips/chip-option.html

@@ -11,6 +11,7 @@
     [_allowFocusWhenDisabled]="true"
     [attr.aria-selected]="ariaSelected"
     [attr.aria-label]="ariaLabel"
+    [attr.aria-description]="ariaDescription"
     role="option">
     <span class="mdc-evolution-chip__graphic mat-mdc-chip-graphic" *ngIf="_hasLeadingGraphic()">
       <ng-content select="mat-chip-avatar, [matChipAvatar]"></ng-content>

src/material/chips/chip-option.spec.ts

@@ -296,6 +296,23 @@ describe('MDC-based Option Chips', () => {
       });
     });
 
+    describe('a11y', () => {
+      it('should apply `ariaLabel` and `ariaDesciption` to the element with option role', () => {
+        testComponent.ariaLabel = 'option name';
+        testComponent.ariaDescription = 'option description';
+
+        fixture.detectChanges();
+
+        const optionElement = fixture.nativeElement.querySelector('[role="option"]') as HTMLElement;
+        expect(optionElement)
+          .withContext('expected to find an element with option role')
+          .toBeTruthy();
+
+        expect(optionElement.getAttribute('aria-label')).toBe('option name');
+        expect(optionElement.getAttribute('aria-description')).toBe('option description');
+      });
+    });
+
     it('should contain a focus indicator inside the text label', () => {
       const label = chipNativeElement.querySelector('.mdc-evolution-chip__text-label');
       expect(label?.querySelector('.mat-mdc-focus-indicator')).toBeTruthy();
@@ -310,7 +327,8 @@ describe('MDC-based Option Chips', () => {
         <mat-chip-option [selectable]="selectable"
                  [color]="color" [selected]="selected" [disabled]="disabled"
                  (destroyed)="chipDestroy($event)"
-                 (selectionChange)="chipSelectionChange($event)">
+                 (selectionChange)="chipSelectionChange($event)"
+                 [aria-label]="ariaLabel" [aria-description]="ariaDescription">
           <span class="avatar" matChipAvatar></span>
           {{name}}
         </mat-chip-option>
@@ -325,6 +343,8 @@ class SingleChip {
   selected: boolean = false;
   selectable: boolean = true;
   shouldShow: boolean = true;
+  ariaLabel: string | null = null;
+  ariaDescription: string | null = null;
 
   chipDestroy: (event?: MatChipEvent) => void = () => {};
   chipSelectionChange: (event?: MatChipSelectionChange) => void = () => {};

src/material/chips/chip-option.ts

@@ -64,6 +64,7 @@ export class MatChipSelectionChange {
     '[class.mat-mdc-chip-with-trailing-icon]': '_hasTrailingIcon()',
     '[attr.tabindex]': 'null',
     '[attr.aria-label]': 'null',
+    '[attr.aria-description]': 'null',
     '[attr.role]': 'role',
     '[id]': 'id',
   },

src/material/chips/chip-row.html

@@ -13,7 +13,8 @@
     [attr.role]="editable ? 'button' : null"
     [tabIndex]="tabIndex"
     [disabled]="disabled"
-    [attr.aria-label]="ariaLabel">
+    [attr.aria-label]="ariaLabel"
+    [attr.aria-description]="ariaDescription">
     <span class="mdc-evolution-chip__graphic mat-mdc-chip-graphic" *ngIf="leadingIcon">
       <ng-content select="mat-chip-avatar, [matChipAvatar]"></ng-content>
     </span>

src/material/chips/chip-row.spec.ts

@@ -332,6 +332,25 @@ describe('MDC-based Row Chips', () => {
         expect(document.activeElement).not.toBe(primaryAction);
       }));
     });
+
+    describe('a11y', () => {
+      it('should apply `ariaLabel` and `ariaDesciption` to the primary gridcell', () => {
+        fixture.componentInstance.ariaLabel = 'chip name';
+        fixture.componentInstance.ariaDescription = 'chip description';
+
+        fixture.detectChanges();
+
+        const primaryGridCell = fixture.nativeElement.querySelector(
+          '[role="gridcell"].mdc-evolution-chip__cell--primary .mat-mdc-chip-action',
+        );
+        expect(primaryGridCell)
+          .withContext('expected to find the grid cell for the primary chip action')
+          .toBeTruthy();
+
+        expect(primaryGridCell.getAttribute('aria-label')).toBe('chip name');
+        expect(primaryGridCell.getAttribute('aria-description')).toBe('chip description');
+      });
+    });
   });
 });
 
@@ -342,7 +361,8 @@ describe('MDC-based Row Chips', () => {
         <mat-chip-row [removable]="removable"
                  [color]="color" [disabled]="disabled" [editable]="editable"
                  (destroyed)="chipDestroy($event)"
-                 (removed)="chipRemove($event)" (edited)="chipEdit($event)">
+                 (removed)="chipRemove($event)" (edited)="chipEdit($event)"
+                 [aria-label]="ariaLabel" [aria-description]="ariaDescription">
           {{name}}
           <button matChipRemove>x</button>
           <span *ngIf="useCustomEditInput" class="projected-edit-input" matChipEditInput></span>
@@ -361,6 +381,8 @@ class SingleChip {
   shouldShow: boolean = true;
   editable: boolean = false;
   useCustomEditInput: boolean = true;
+  ariaLabel: string | null = null;
+  ariaDescription: string | null = null;
 
   chipDestroy: (event?: MatChipEvent) => void = () => {};
   chipRemove: (event?: MatChipEvent) => void = () => {};

src/material/chips/chip-row.ts

@@ -64,6 +64,7 @@ export interface MatChipEditedEvent extends MatChipEvent {
     '[id]': 'id',
     '[attr.tabindex]': 'null',
     '[attr.aria-label]': 'null',
+    '[attr.aria-description]': 'null',
     '[attr.role]': 'role',
     '(mousedown)': '_mousedown($event)',
     '(dblclick)': '_doubleclick($event)',

src/material/chips/chip.ts

@@ -150,6 +150,9 @@ export class MatChip
   /** ARIA label for the content of the chip. */
   @Input('aria-label') ariaLabel: string | null = null;
 
+  /** ARIA description for the content of the chip. */
+  @Input('aria-description') ariaDescription: string | null = null;
+
   private _textElement!: HTMLElement;
 
   /**

tools/public_api_guard/material/chips.md

@@ -65,6 +65,7 @@ export const MAT_CHIPS_DEFAULT_OPTIONS: InjectionToken<MatChipsDefaultOptions>;
 export class MatChip extends _MatChipMixinBase implements AfterViewInit, CanColor, CanDisableRipple, CanDisable, HasTabIndex, OnDestroy {
     constructor(_changeDetectorRef: ChangeDetectorRef, elementRef: ElementRef<HTMLElement>, _ngZone: NgZone, _focusMonitor: FocusMonitor, _document: any, animationMode?: string, _globalRippleOptions?: RippleGlobalOptions | undefined, tabIndex?: string);
     _animationsDisabled: boolean;
+    ariaDescription: string | null;
     ariaLabel: string | null;
     protected basicChipAttrName: string;
     // (undocumented)
@@ -113,7 +114,7 @@ export class MatChip extends _MatChipMixinBase implements AfterViewInit, CanColo
     // (undocumented)
     protected _value: any;
     // (undocumented)
-    static ɵcmp: i0.ɵɵComponentDeclaration<MatChip, "mat-basic-chip, mat-chip", ["matChip"], { "color": "color"; "disabled": "disabled"; "disableRipple": "disableRipple"; "tabIndex": "tabIndex"; "role": "role"; "id": "id"; "ariaLabel": "aria-label"; "value": "value"; "removable": "removable"; "highlighted": "highlighted"; }, { "removed": "removed"; "destroyed": "destroyed"; }, ["leadingIcon", "trailingIcon", "removeIcon"], ["mat-chip-avatar, [matChipAvatar]", "*", "mat-chip-trailing-icon,[matChipRemove],[matChipTrailingIcon]"], false, never>;
+    static ɵcmp: i0.ɵɵComponentDeclaration<MatChip, "mat-basic-chip, mat-chip", ["matChip"], { "color": "color"; "disabled": "disabled"; "disableRipple": "disableRipple"; "tabIndex": "tabIndex"; "role": "role"; "id": "id"; "ariaLabel": "aria-label"; "ariaDescription": "aria-description"; "value": "value"; "removable": "removable"; "highlighted": "highlighted"; }, { "removed": "removed"; "destroyed": "destroyed"; }, ["leadingIcon", "trailingIcon", "removeIcon"], ["mat-chip-avatar, [matChipAvatar]", "*", "mat-chip-trailing-icon,[matChipRemove],[matChipTrailingIcon]"], false, never>;
     // (undocumented)
     static ɵfac: i0.ɵɵFactoryDeclaration<MatChip, [null, null, null, null, null, { optional: true; }, { optional: true; }, { attribute: "tabindex"; }]>;
 }