fix(material-experimental/mdc-chips): support home/end in chip grid (#18052)

Adds support for the "Home" and "End" keys to the `mat-chip-grid`, similarly to the `mat-chip-listbox`.

Author: crisbeto

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

@@ -7,7 +7,9 @@ import {
   LEFT_ARROW,
   RIGHT_ARROW,
   SPACE,
-  TAB
+  TAB,
+  HOME,
+  END
 } from '@angular/cdk/keycodes';
 import {
   createFakeEvent,
@@ -443,6 +445,55 @@ describe('MDC-based MatChipGrid', () => {
         expect(manager.activeRowIndex).toBe(0);
         expect(manager.activeColumnIndex).toBe(0);
       });
+
+      it('should move focus to the first chip when pressing HOME', () => {
+        setupStandardGrid();
+        manager = chipGridInstance._keyManager;
+
+        const nativeChips = chipGridNativeElement.querySelectorAll('mat-chip-row');
+        const lastNativeChip = nativeChips[nativeChips.length - 1] as HTMLElement;
+
+        const HOME_EVENT: KeyboardEvent =
+          createKeyboardEvent('keydown', HOME, undefined, lastNativeChip);
+        const array = chips.toArray();
+        const lastItem = array[array.length - 1];
+
+        lastItem.focus();
+        expect(manager.activeRowIndex).toBe(4);
+        expect(manager.activeColumnIndex).toBe(0);
+
+        chipGridInstance._keydown(HOME_EVENT);
+        fixture.detectChanges();
+
+        expect(HOME_EVENT.defaultPrevented).toBe(true);
+        expect(manager.activeRowIndex).toBe(0);
+        expect(manager.activeColumnIndex).toBe(0);
+      });
+
+      it('should move focus to the last chip when pressing END', () => {
+        setupStandardGrid();
+        manager = chipGridInstance._keyManager;
+
+        const nativeChips = chipGridNativeElement.querySelectorAll('mat-chip-row');
+        const firstNativeChip = nativeChips[0] as HTMLElement;
+
+        const END_EVENT: KeyboardEvent =
+          createKeyboardEvent('keydown', END, undefined, firstNativeChip);
+        const array = chips.toArray();
+        const firstItem = array[0];
+
+        firstItem.focus();
+        expect(manager.activeRowIndex).toBe(0);
+        expect(manager.activeColumnIndex).toBe(0);
+
+        chipGridInstance._keydown(END_EVENT);
+        fixture.detectChanges();
+
+        expect(END_EVENT.defaultPrevented).toBe(true);
+        expect(manager.activeRowIndex).toBe(4);
+        expect(manager.activeColumnIndex).toBe(0);
+      });
+
     });
   });
 

src/material-experimental/mdc-chips/chip-grid.ts

@@ -8,7 +8,7 @@
 
 import {Directionality} from '@angular/cdk/bidi';
 import {BooleanInput, coerceBooleanProperty} from '@angular/cdk/coercion';
-import {BACKSPACE, TAB} from '@angular/cdk/keycodes';
+import {BACKSPACE, TAB, HOME, END} from '@angular/cdk/keycodes';
 import {
   AfterContentInit,
   AfterViewInit,
@@ -400,17 +400,27 @@ export class MatChipGrid extends _MatChipGridMixinBase implements AfterContentIn
   /** Handles custom keyboard events. */
   _keydown(event: KeyboardEvent) {
     const target = event.target as HTMLElement;
+    const keyCode = event.keyCode;
+    const manager = this._keyManager;
 
     // If they are on an empty input and hit backspace, focus the last chip
-    if (event.keyCode === BACKSPACE && this._isEmptyInput(target)) {
+    if (keyCode === BACKSPACE && this._isEmptyInput(target)) {
       if (this._chips.length) {
-        this._keyManager.setLastCellActive();
+        manager.setLastCellActive();
       }
       event.preventDefault();
-    } else if (event.keyCode === TAB && target.id !== this._chipInput!.id ) {
+    } else if (keyCode === TAB && target.id !== this._chipInput!.id ) {
       this._allowFocusEscape();
     } else if (this._originatesFromChip(event)) {
-      this._keyManager.onKeydown(event);
+      if (keyCode === HOME) {
+        manager.setFirstCellActive();
+        event.preventDefault();
+      } else if (keyCode === END) {
+        manager.setLastCellActive();
+        event.preventDefault();
+      } else {
+        manager.onKeydown(event);
+      }
     }
     this.stateChanges.next();
   }