feat(material/chips): make ChipInput optional for MatChipGrid (angular#31693)

Author: adolgachev

goldens/material/chips/index.api.md

@@ -189,7 +189,7 @@ export class MatChipGrid extends MatChipSet implements AfterContentInit, AfterVi
     _blur(): void;
     readonly change: EventEmitter<MatChipGridChange>;
     get chipBlurChanges(): Observable<MatChipEvent>;
-    protected _chipInput: MatChipTextControl;
+    protected _chipInput?: MatChipTextControl;
     // (undocumented)
     _chips: QueryList<MatChipRow>;
     readonly controlType: string;
@@ -216,8 +216,6 @@ export class MatChipGrid extends MatChipSet implements AfterContentInit, AfterVi
     // (undocumented)
     ngAfterContentInit(): void;
     // (undocumented)
-    ngAfterViewInit(): void;
-    // (undocumented)
     ngControl: NgControl;
     // (undocumented)
     ngDoCheck(): void;

src/dev-app/chips/chips-demo.html

@@ -230,6 +230,31 @@ <h4>Options</h4>
         <mat-checkbox name="addOnBlur" [(ngModel)]="addOnBlur">Add on Blur</mat-checkbox>
       </p>
 
+      <h4>Chip grid with no Input</h4>
+
+      <mat-form-field class="demo-has-chip-list">
+        <mat-chip-grid #chipGrid3 [(ngModel)]="selectedPeople" required [disabled]="disableInputs">
+          @for (person of people; track person) {
+            <mat-chip-row
+              [editable]="editable"
+              (removed)="remove(person)"
+              (edited)="edit(person, $event)">
+              @if (showEditIcon) {
+                <button matChipEdit aria-label="Edit contributor">
+                  <mat-icon>edit</mat-icon>
+                </button>
+              }
+              @if (peopleWithAvatar && person.avatar) {
+                <mat-chip-avatar>{{person.avatar}}</mat-chip-avatar>
+              }
+              {{person.name}}
+              <button matChipRemove aria-label="Remove contributor">
+                <mat-icon>close</mat-icon>
+              </button>
+            </mat-chip-row>
+          }
+        </mat-chip-grid>
+      </mat-form-field>      
     </mat-card-content>
   </mat-card>
 

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

@@ -588,6 +588,74 @@ describe('MatChipGrid', () => {
     });
   });
 
+  describe('ChipGrid without input', () => {
+    it('should not throw when used without a chip input', () => {
+      expect(() => createComponent(ChipGridWithoutInput)).not.toThrow();
+    });
+
+    it('should be able to focus the first chip', () => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      chipGridInstance.focus();
+      fixture.detectChanges();
+      expect(document.activeElement).toBe(primaryActions[0]);
+    });
+
+    it('should not do anything on focus if there are no chips', () => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      (testComponent as unknown as ChipGridWithoutInput).chips = [];
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+
+      chipGridInstance.focus();
+      fixture.detectChanges();
+
+      expect(chipGridNativeElement.contains(document.activeElement)).toBe(false);
+    });
+
+    it('should have a default id on the component instance', () => {
+      createComponent(ChipGridWithoutInput);
+      expect(chipGridInstance.id).toMatch(/^mat-chip-grid-\w+$/);
+    });
+
+    it('should have empty getters that work without an input', () => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      expect(chipGridInstance.empty).toBe(false);
+
+      (testComponent as unknown as ChipGridWithoutInput).chips = [];
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+
+      expect(chipGridInstance.empty).toBe(true);
+    });
+
+    it('should have a placeholder getter that works without an input', () => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      (testComponent as unknown as ChipGridWithoutInput).placeholder = 'Hello';
+      fixture.changeDetectorRef.markForCheck();
+      fixture.detectChanges();
+      expect(chipGridInstance.placeholder).toBe('Hello');
+    });
+
+    it('should have a focused getter that works without an input', () => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      expect(chipGridInstance.focused).toBe(false);
+
+      chipGridInstance.focus();
+      fixture.detectChanges();
+
+      expect(chipGridInstance.focused).toBe(true);
+    });
+
+    it('should set aria-describedby on the grid when there is no input', fakeAsync(() => {
+      const fixture = createComponent(ChipGridWithoutInput);
+      const hint = fixture.debugElement.query(By.css('mat-hint')).nativeElement;
+      flush();
+      fixture.detectChanges();
+
+      expect(chipGridNativeElement.getAttribute('aria-describedby')).toBe(hint.id);
+    }));
+  });
+
   describe('with chip remove', () => {
     it('should properly focus next item if chip is removed through click', fakeAsync(() => {
       // TODO(crisbeto): this test fails without the NoopAnimationsModule for some reason.
@@ -1234,3 +1302,22 @@ class ChipGridWithRemove {
     this.chips.splice(event.chip.value, 1);
   }
 }
+
+@Component({
+  template: `
+    <mat-form-field>
+      <mat-label>Foods</mat-label>
+      <mat-chip-grid #chipGrid [placeholder]="placeholder">
+        @for (food of chips; track food) {
+          <mat-chip-row>{{ food }}</mat-chip-row>
+        }
+      </mat-chip-grid>
+      <mat-hint>Some hint</mat-hint>
+    </mat-form-field>
+  `,
+  imports: [MatChipGrid, MatChipRow, MatFormField, MatLabel, MatHint],
+})
+class ChipGridWithoutInput {
+  chips = ['Pizza', 'Pasta', 'Tacos'];
+  placeholder: string;
+}

src/material/chips/chip-grid.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
+import {_IdGenerator} from '@angular/cdk/a11y';
 import {DOWN_ARROW, hasModifierKey, TAB, UP_ARROW} from '@angular/cdk/keycodes';
 import {
   AfterContentInit,
@@ -96,10 +97,11 @@ export class MatChipGrid
   readonly controlType: string = 'mat-chip-grid';
 
   /** The chip input to add more chips */
-  protected _chipInput: MatChipTextControl;
+  protected _chipInput?: MatChipTextControl;
 
   protected override _defaultRole = 'grid';
   private _errorStateTracker: _ErrorStateTracker;
+  private _uid = inject(_IdGenerator).getId('mat-chip-grid-');
 
   /**
    * List of element ids to propagate to the chipInput's aria-describedby attribute.
@@ -137,7 +139,7 @@ export class MatChipGrid
    * @docs-private
    */
   get id(): string {
-    return this._chipInput.id;
+    return this._chipInput ? this._chipInput.id : this._uid;
   }
 
   /**
@@ -166,7 +168,7 @@ export class MatChipGrid
 
   /** Whether any chips or the matChipInput inside of this chip-grid has focus. */
   override get focused(): boolean {
-    return this._chipInput.focused || this._hasFocusedChip();
+    return this._chipInput?.focused || this._hasFocusedChip();
   }
 
   /**
@@ -285,14 +287,6 @@ export class MatChipGrid
       .subscribe(() => this.stateChanges.next());
   }
 
-  override ngAfterViewInit() {
-    super.ngAfterViewInit();
-
-    if (!this._chipInput && (typeof ngDevMode === 'undefined' || ngDevMode)) {
-      throw Error('mat-chip-grid must be used in combination with matChipInputFor.');
-    }
-  }
-
   ngDoCheck() {
     if (this.ngControl) {
       // We need to re-evaluate this on every change detection cycle, because there are some
@@ -311,6 +305,9 @@ export class MatChipGrid
   registerInput(inputElement: MatChipTextControl): void {
     this._chipInput = inputElement;
     this._chipInput.setDescribedByIds(this._ariaDescribedbyIds);
+
+    // If ids were already attached to host element, can now remove in favor of chipInput
+    this._elementRef.nativeElement.removeAttribute('aria-describedby');
   }
 
   /**
@@ -328,14 +325,18 @@ export class MatChipGrid
    * are no eligible chips.
    */
   override focus(): void {
-    if (this.disabled || this._chipInput.focused) {
+    if (this.disabled || this._chipInput?.focused) {
       return;
     }
 
     if (!this._chips.length || this._chips.first.disabled) {
+      if (!this._chipInput) {
+        return;
+      }
+
       // Delay until the next tick, because this can cause a "changed after checked"
       // error if the input does something on focus (e.g. opens an autocomplete).
-      Promise.resolve().then(() => this._chipInput.focus());
+      Promise.resolve().then(() => this._chipInput!.focus());
     } else {
       const activeItem = this._keyManager.activeItem;
 
@@ -354,7 +355,11 @@ export class MatChipGrid
    * @docs-private
    */
   get describedByIds(): string[] {
-    return this._chipInput?.describedByIds || [];
+    if (this._chipInput) {
+      return this._chipInput.describedByIds || [];
+    }
+    const existing = this._elementRef.nativeElement.getAttribute('aria-describedby');
+    return existing ? existing.split(' ') : [];
   }
 
   /**
@@ -365,7 +370,14 @@ export class MatChipGrid
     // We must keep this up to date to handle the case where ids are set
     // before the chip input is registered.
     this._ariaDescribedbyIds = ids;
-    this._chipInput?.setDescribedByIds(ids);
+
+    if (this._chipInput) {
+      this._chipInput.setDescribedByIds(ids);
+    } else if (ids.length) {
+      this._elementRef.nativeElement.setAttribute('aria-describedby', ids.join(' '));
+    } else {
+      this._elementRef.nativeElement.removeAttribute('aria-describedby');
+    }
   }
 
   /**
@@ -429,7 +441,7 @@ export class MatChipGrid
    * it back to the first chip, creating a focus trap, if it user tries to tab away.
    */
   protected override _allowFocusEscape() {
-    if (!this._chipInput.focused) {
+    if (!this._chipInput?.focused) {
       super._allowFocusEscape();
     }
   }
@@ -441,7 +453,7 @@ export class MatChipGrid
 
     if (keyCode === TAB) {
       if (
-        this._chipInput.focused &&
+        this._chipInput?.focused &&
         hasModifierKey(event, 'shiftKey') &&
         this._chips.length &&
         !this._chips.last.disabled
@@ -459,7 +471,7 @@ export class MatChipGrid
         // disabled chip left in the list.
         super._allowFocusEscape();
       }
-    } else if (!this._chipInput.focused) {
+    } else if (!this._chipInput?.focused) {
       // 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

src/material/chips/chips.md

@@ -36,7 +36,7 @@ Users can move through the chips using the arrow keys and select/deselect them w
 
 Use `<mat-chip-grid>` and `<mat-chip-row>` for assisting users with text entry.
 
-Chips are always used inside a container. To create chips connected to an input field, start by creating a `<mat-chip-grid>` as the container. Add an `<input/>` element, and register it to the `<mat-chip-grid>` by passing the `matChipInputFor` Input. Always use an `<input/>` element with `<mat-chip-grid>`. Nest a `<mat-chip-row>` element inside the `<mat-chip-grid>` for each piece of data entered by the user. An example of using chips for text input.
+Chips are always used inside a container. To create chips connected to an input field, start by creating a `<mat-chip-grid>` as the container. Add an `<input/>` element, and register it to the `<mat-chip-grid>` by passing the `matChipInputFor` Input. Nest a `<mat-chip-row>` element inside the `<mat-chip-grid>` for each piece of data entered by the user. An example of using chips for text input.
 
 <!-- example(chips-input) -->