fix(material/chips): navigate between rows on up/down arrow

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

@@ -3,13 +3,15 @@ import {Direction, Directionality} from '@angular/cdk/bidi';
 import {
   BACKSPACE,
   DELETE,
+  DOWN_ARROW,
   END,
   ENTER,
   HOME,
   LEFT_ARROW,
   RIGHT_ARROW,
   SPACE,
   TAB,
+  UP_ARROW,
 } from '@angular/cdk/keycodes';
 import {
   createKeyboardEvent,
@@ -309,6 +311,48 @@ describe('MDC-based MatChipGrid', () => {
             .withContext('Expected focused item not to have changed.')
             .toBe(previousActiveElement);
         });
+
+        it('should focus primary action in next row when pressing DOWN ARROW on primary action', () => {
+          chips.first.focus();
+          expect(document.activeElement).toBe(primaryActions[0]);
+
+          dispatchKeyboardEvent(primaryActions[0], 'keydown', DOWN_ARROW);
+          fixture.detectChanges();
+
+          expect(document.activeElement).toBe(primaryActions[1]);
+        });
+
+        it('should focus primary action in previous row when pressing UP ARROW on primary action', () => {
+          const lastIndex = primaryActions.length - 1;
+          chips.last.focus();
+          expect(document.activeElement).toBe(primaryActions[lastIndex]);
+
+          dispatchKeyboardEvent(primaryActions[lastIndex], 'keydown', UP_ARROW);
+          fixture.detectChanges();
+
+          expect(document.activeElement).toBe(primaryActions[lastIndex - 1]);
+        });
+
+        it('should focus(trailing action in next row when pressing DOWN ARROW on(trailing action', () => {
+          trailingActions[0].focus();
+          expect(document.activeElement).toBe(trailingActions[0]);
+
+          dispatchKeyboardEvent(trailingActions[0], 'keydown', DOWN_ARROW);
+          fixture.detectChanges();
+
+          expect(document.activeElement).toBe(trailingActions[1]);
+        });
+
+        it('should focus trailing action in previous row when pressing UP ARROW on trailing action', () => {
+          const lastIndex = trailingActions.length - 1;
+          trailingActions[lastIndex].focus();
+          expect(document.activeElement).toBe(trailingActions[lastIndex]);
+
+          dispatchKeyboardEvent(trailingActions[lastIndex], 'keydown', UP_ARROW);
+          fixture.detectChanges();
+
+          expect(document.activeElement).toBe(trailingActions[lastIndex - 1]);
+        });
       });
 
       describe('RTL', () => {
@@ -1034,11 +1078,8 @@ describe('MDC-based MatChipGrid', () => {
   template: `
     <mat-chip-grid [tabIndex]="tabIndex" [role]="role" #chipGrid>
       @for (i of chips; track i) {
-  <mat-chip-row
-                    [editable]="editable">
-        {{name}} {{i + 1}}
-      </mat-chip-row>
-}
+        <mat-chip-row [editable]="editable">{{name}} {{i + 1}}</mat-chip-row>
+      }
     </mat-chip-grid>
     <input name="test" [matChipInputFor]="chipGrid"/>`,
 })
@@ -1056,8 +1097,8 @@ class StandardChipGrid {
       <mat-label>Add a chip</mat-label>
       <mat-chip-grid #chipGrid>
         @for (chip of chips; track chip) {
-  <mat-chip-row (removed)="remove(chip)">{{chip}}</mat-chip-row>
-}
+          <mat-chip-row (removed)="remove(chip)">{{chip}}</mat-chip-row>
+        }
       </mat-chip-grid>
       <input name="test" [matChipInputFor]="chipGrid"/>
     </mat-form-field>
@@ -1081,10 +1122,10 @@ class FormFieldChipGrid {
       <mat-label>New food...</mat-label>
       <mat-chip-grid #chipGrid placeholder="Food" [formControl]="control">
         @for (food of foods; track food) {
-  <mat-chip-row [value]="food.value" (removed)="remove(food)">
-          {{ food.viewValue }}
-        </mat-chip-row>
-}
+          <mat-chip-row [value]="food.value" (removed)="remove(food)">
+            {{ food.viewValue }}
+          </mat-chip-row>
+        }
       </mat-chip-grid>
       <input
           [matChipInputFor]="chipGrid"
@@ -1143,10 +1184,8 @@ class InputChipGrid {
   <mat-form-field>
     <mat-chip-grid #chipGrid [formControl]="formControl">
       @for (food of foods; track food) {
-  <mat-chip-row [value]="food.value">
-      {{food.viewValue}}
-      </mat-chip-row>
-}
+        <mat-chip-row [value]="food.value">{{food.viewValue}}</mat-chip-row>
+      }
     </mat-chip-grid>
     <input name="test" [matChipInputFor]="chipGrid"/>
     <mat-hint>Please select a chip, or type to add a new chip</mat-hint>
@@ -1179,8 +1218,8 @@ class ChipGridWithFormErrorMessages {
   template: `
     <mat-chip-grid #chipGrid>
       @for (i of numbers; track i) {
-  <mat-chip-row (removed)="remove(i)">{{i}}</mat-chip-row>
-}
+        <mat-chip-row (removed)="remove(i)">{{i}}</mat-chip-row>
+      }
       <input name="test" [matChipInputFor]="chipGrid"/>
     </mat-chip-grid>`,
   animations: [
@@ -1208,11 +1247,11 @@ class StandardChipGridWithAnimations {
     <mat-form-field>
       <mat-chip-grid #chipGrid>
         @for (i of chips; track i) {
-  <mat-chip-row [value]="i" (removed)="removeChip($event)">
-          Chip {{i + 1}}
-          <span matChipRemove>Remove</span>
-        </mat-chip-row>
-}
+          <mat-chip-row [value]="i" (removed)="removeChip($event)">
+            Chip {{i + 1}}
+            <span matChipRemove>Remove</span>
+          </mat-chip-row>
+        }
       </mat-chip-grid>
       <input name="test" [matChipInputFor]="chipGrid"/>
     </mat-form-field>

src/material/chips/chip-grid.ts

@@ -7,7 +7,7 @@
  */
 
 import {Directionality} from '@angular/cdk/bidi';
-import {hasModifierKey, TAB} from '@angular/cdk/keycodes';
+import {DOWN_ARROW, hasModifierKey, TAB, UP_ARROW} from '@angular/cdk/keycodes';
 import {
   AfterContentInit,
   AfterViewInit,
@@ -426,7 +426,10 @@ export class MatChipGrid
 
   /** Handles custom keyboard events. */
   override _handleKeydown(event: KeyboardEvent) {
-    if (event.keyCode === TAB) {
+    const keyCode = event.keyCode;
+    const activeItem = this._keyManager.activeItem;
+
+    if (keyCode === TAB) {
       if (
         this._chipInput.focused &&
         hasModifierKey(event, 'shiftKey') &&
@@ -435,8 +438,8 @@ export class MatChipGrid
       ) {
         event.preventDefault();
 
-        if (this._keyManager.activeItem) {
-          this._keyManager.setActiveItem(this._keyManager.activeItem);
+        if (activeItem) {
+          this._keyManager.setActiveItem(activeItem);
         } else {
           this._focusLastChip();
         }
@@ -447,7 +450,25 @@ export class MatChipGrid
         super._allowFocusEscape();
       }
     } else if (!this._chipInput.focused) {
-      super._handleKeydown(event);
+      // The up and down arrows are supposed to navigate between the individual rows in the grid.
+      // We do this by filtering the actions down to the ones that have the same `_isPrimary`
+      // flag as the active action and moving focus between them ourseles instead of delegating
+      // to the key manager. For more information, see #29359 and:
+      // https://www.w3.org/WAI/ARIA/apg/patterns/grid/examples/layout-grids/#ex2_label
+      if ((keyCode === UP_ARROW || keyCode === DOWN_ARROW) && activeItem) {
+        const eligibleActions = this._chipActions.filter(
+          action => action._isPrimary === activeItem._isPrimary && !this._skipPredicate(action),
+        );
+        const currentIndex = eligibleActions.indexOf(activeItem);
+        const delta = event.keyCode === UP_ARROW ? -1 : 1;
+
+        event.preventDefault();
+        if (currentIndex > -1 && this._isValidIndex(currentIndex + delta)) {
+          this._keyManager.setActiveItem(eligibleActions[currentIndex + delta]);
+        }
+      } else {
+        super._handleKeydown(event);
+      }
     }
 
     this.stateChanges.next();