feat(bottom-sheet): add result param when dismissing bottom sheet (#9810)

Something that came up while doing the docs. Adds the ability for the consumer to pass back a result from a bottom sheet. Also adds a test for `afterDismissed` since it didn't have one.

src/lib/bottom-sheet/bottom-sheet-ref.ts

@@ -18,7 +18,7 @@ import {MatBottomSheetContainer} from './bottom-sheet-container';
 /**
  * Reference to a bottom sheet dispatched from the bottom sheet service.
  */
-export class MatBottomSheetRef<T = any> {
+export class MatBottomSheetRef<T = any, R = any> {
   /** Instance of the component making up the content of the bottom sheet. */
   instance: T;
 
@@ -29,11 +29,14 @@ export class MatBottomSheetRef<T = any> {
   containerInstance: MatBottomSheetContainer;
 
   /** Subject for notifying the user that the bottom sheet has been dismissed. */
-  private readonly _afterDismissed = new Subject<void>();
+  private readonly _afterDismissed = new Subject<R | undefined>();
 
   /** Subject for notifying the user that the bottom sheet has opened and appeared. */
   private readonly _afterOpened = new Subject<void>();
 
+  /** Result to be passed down to the `afterDismissed` stream. */
+  private _result: R | undefined;
+
   constructor(containerInstance: MatBottomSheetContainer, private _overlayRef: OverlayRef) {
     this.containerInstance = containerInstance;
 
@@ -54,7 +57,7 @@ export class MatBottomSheetRef<T = any> {
     )
     .subscribe(() => {
       this._overlayRef.dispose();
-      this._afterDismissed.next();
+      this._afterDismissed.next(this._result);
       this._afterDismissed.complete();
     });
 
@@ -66,8 +69,11 @@ export class MatBottomSheetRef<T = any> {
     }
   }
 
-  /** Dismisses the bottom sheet. */
-  dismiss(): void {
+  /**
+   * Dismisses the bottom sheet.
+   * @param result Data to be passed back to the bottom sheet opener.
+   */
+  dismiss(result?: R): void {
     if (!this._afterDismissed.closed) {
       // Transition the backdrop in parallel to the bottom sheet.
       this.containerInstance._animationStateChanged.pipe(
@@ -75,12 +81,13 @@ export class MatBottomSheetRef<T = any> {
         take(1)
       ).subscribe(() => this._overlayRef.detachBackdrop());
 
+      this._result = result;
       this.containerInstance.exit();
     }
   }
 
   /** Gets an observable that is notified when the bottom sheet is finished closing. */
-  afterDismissed(): Observable<void> {
+  afterDismissed(): Observable<R | undefined> {
     return this._afterDismissed.asObservable();
   }
 

src/lib/bottom-sheet/bottom-sheet.spec.ts

@@ -295,6 +295,34 @@ describe('MatBottomSheet', () => {
       tick(500);
     }));
 
+  it('should emit after being dismissed', fakeAsync(() => {
+    const bottomSheetRef = bottomSheet.open(PizzaMsg);
+    const spy = jasmine.createSpy('afterDismissed spy');
+
+    bottomSheetRef.afterDismissed().subscribe(spy);
+    viewContainerFixture.detectChanges();
+
+    bottomSheetRef.dismiss();
+    viewContainerFixture.detectChanges();
+    flush();
+
+    expect(spy).toHaveBeenCalledTimes(1);
+  }));
+
+  it('should be able to pass a result back to the dismissed stream', fakeAsync(() => {
+    const bottomSheetRef = bottomSheet.open<PizzaMsg, any, number>(PizzaMsg);
+    const spy = jasmine.createSpy('afterDismissed spy');
+
+    bottomSheetRef.afterDismissed().subscribe(spy);
+    viewContainerFixture.detectChanges();
+
+    bottomSheetRef.dismiss(1337);
+    viewContainerFixture.detectChanges();
+    flush();
+
+    expect(spy).toHaveBeenCalledWith(1337);
+  }));
+
   describe('passing in data', () => {
     it('should be able to pass in data', () => {
       const config = {

src/lib/bottom-sheet/bottom-sheet.ts

@@ -39,18 +39,18 @@ export class MatBottomSheet {
       private _injector: Injector,
       @Optional() @SkipSelf() private _parentBottomSheet: MatBottomSheet) {}
 
-  open<T, D = any>(component: ComponentType<T>,
-                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T>;
-  open<T, D = any>(template: TemplateRef<T>,
-                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T>;
+  open<T, D = any, R = any>(component: ComponentType<T>,
+                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T, R>;
+  open<T, D = any, R = any>(template: TemplateRef<T>,
+                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T, R>;
 
-  open<T, D = any>(componentOrTemplateRef: ComponentType<T> | TemplateRef<T>,
-                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T> {
+  open<T, D = any, R = any>(componentOrTemplateRef: ComponentType<T> | TemplateRef<T>,
+                   config?: MatBottomSheetConfig<D>): MatBottomSheetRef<T, R> {
 
     const _config = _applyConfigDefaults(config);
     const overlayRef = this._createOverlay(_config);
     const container = this._attachContainer(overlayRef, _config);
-    const ref = new MatBottomSheetRef<T>(container, overlayRef);
+    const ref = new MatBottomSheetRef<T, R>(container, overlayRef);
 
     if (componentOrTemplateRef instanceof TemplateRef) {
       container.attachTemplatePortal(new TemplatePortal<T>(componentOrTemplateRef, null!, {