feat(datepicker): add animation to calendar popup (#8999)

Adds an animation when opening and closing the datepicker's calendar.

BREAKING CHANGES:
* `MatDatePicker` now requires an animations module to be loaded

src/lib/datepicker/datepicker-animations.ts

@@ -0,0 +1,36 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {
+  animate,
+  state,
+  style,
+  transition,
+  trigger,
+  AnimationTriggerMetadata,
+} from '@angular/animations';
+
+/** Animations used by the Material datepicker. */
+export const matDatepickerAnimations: {
+  readonly transformPanel: AnimationTriggerMetadata;
+  readonly fadeInCalendar: AnimationTriggerMetadata;
+} = {
+  /** Transforms the height of the datepicker's calendar. */
+  transformPanel: trigger('transformPanel', [
+    state('void', style({opacity: 0, transform: 'scale(1, 0)'})),
+    state('enter', style({opacity: 1, transform: 'scale(1, 1)'})),
+    transition('void => enter', animate('400ms cubic-bezier(0.25, 0.8, 0.25, 1)')),
+    transition('* => void', animate('100ms linear', style({opacity: 0})))
+  ]),
+
+  /** Fades in the content of the calendar. */
+  fadeInCalendar: trigger('fadeInCalendar', [
+    state('void', style({opacity: 0})),
+    state('enter', style({opacity: 1})),
+    transition('void => *', animate('400ms 100ms cubic-bezier(0.55, 0, 0.55, 0.2)'))
+  ])
+};

src/lib/datepicker/datepicker-content.html

@@ -7,6 +7,7 @@
     [maxDate]="datepicker._maxDate"
     [dateFilter]="datepicker._dateFilter"
     [selected]="datepicker._selected"
+    [@fadeInCalendar]="'enter'"
     (selectedChange)="datepicker._select($event)"
     (yearSelected)="datepicker._selectYear($event)"
     (monthSelected)="datepicker._selectMonth($event)"

src/lib/datepicker/datepicker-content.scss

@@ -29,6 +29,7 @@ $mat-datepicker-touch-max-height: 788px;
 
   display: block;
   border-radius: 2px;
+  transform-origin: top center;
 
   .mat-calendar {
     width: $mat-datepicker-non-touch-calendar-width;
@@ -36,6 +37,10 @@ $mat-datepicker-touch-max-height: 788px;
   }
 }
 
+.mat-datepicker-content-above {
+  transform-origin: bottom center;
+}
+
 .mat-datepicker-content-touch {
   @include mat-elevation(0);
 

src/lib/datepicker/datepicker.spec.ts

@@ -98,40 +98,19 @@ describe('MatDatepicker', () => {
             .not.toBeNull();
       });
 
-      it('should pass the datepicker theme color to the overlay', fakeAsync(() => {
-        testComponent.datepicker.color = 'primary';
-        testComponent.datepicker.open();
-        fixture.detectChanges();
-
-        let contentEl = document.querySelector('.mat-datepicker-content')!;
-
-        expect(contentEl.classList).toContain('mat-primary');
-
-        testComponent.datepicker.close();
-        fixture.detectChanges();
-        flush();
-
-        testComponent.datepicker.color = 'warn';
-        testComponent.datepicker.open();
-
-        contentEl = document.querySelector('.mat-datepicker-content')!;
-        fixture.detectChanges();
-
-        expect(contentEl.classList).toContain('mat-warn');
-        expect(contentEl.classList).not.toContain('mat-primary');
-      }));
-
-      it('should open datepicker if opened input is set to true', () => {
+      it('should open datepicker if opened input is set to true', fakeAsync(() => {
         testComponent.opened = true;
         fixture.detectChanges();
+        flush();
 
         expect(document.querySelector('.mat-datepicker-content')).not.toBeNull();
 
         testComponent.opened = false;
         fixture.detectChanges();
+        flush();
 
         expect(document.querySelector('.mat-datepicker-content')).toBeNull();
-      });
+      }));
 
       it('open in disabled mode should not open the calendar', () => {
         testComponent.disabled = true;
@@ -165,7 +144,7 @@ describe('MatDatepicker', () => {
         fixture.detectChanges();
         flush();
 
-        let popup = document.querySelector('.cdk-overlay-pane')!;
+        const popup = document.querySelector('.cdk-overlay-pane')!;
         expect(popup).not.toBeNull();
         expect(parseInt(getComputedStyle(popup).height as string)).not.toBe(0);
 
@@ -211,6 +190,7 @@ describe('MatDatepicker', () => {
 
         testComponent.datepicker.open();
         fixture.detectChanges();
+        flush();
 
         expect(document.querySelector('mat-dialog-container')).not.toBeNull();
         expect(testComponent.datepickerInput.value).toEqual(new Date(2020, JAN, 1));
@@ -224,28 +204,30 @@ describe('MatDatepicker', () => {
         expect(testComponent.datepickerInput.value).toEqual(new Date(2020, JAN, 2));
       }));
 
-      it('setting selected via enter press should update input and close calendar', () => {
-        testComponent.touch = true;
-        fixture.detectChanges();
+      it('setting selected via enter press should update input and close calendar',
+        fakeAsync(() => {
+          testComponent.touch = true;
+          fixture.detectChanges();
 
-        testComponent.datepicker.open();
-        fixture.detectChanges();
+          testComponent.datepicker.open();
+          fixture.detectChanges();
+          flush();
 
-        expect(document.querySelector('mat-dialog-container')).not.toBeNull();
-        expect(testComponent.datepickerInput.value).toEqual(new Date(2020, JAN, 1));
+          expect(document.querySelector('mat-dialog-container')).not.toBeNull();
+          expect(testComponent.datepickerInput.value).toEqual(new Date(2020, JAN, 1));
 
-        let calendarBodyEl = document.querySelector('.mat-calendar-body') as HTMLElement;
+          let calendarBodyEl = document.querySelector('.mat-calendar-body') as HTMLElement;
 
-        dispatchKeyboardEvent(calendarBodyEl, 'keydown', RIGHT_ARROW);
-        fixture.detectChanges();
-        dispatchKeyboardEvent(calendarBodyEl, 'keydown', ENTER);
-        fixture.detectChanges();
+          dispatchKeyboardEvent(calendarBodyEl, 'keydown', RIGHT_ARROW);
+          fixture.detectChanges();
+          flush();
+          dispatchKeyboardEvent(calendarBodyEl, 'keydown', ENTER);
+          fixture.detectChanges();
+          flush();
 
-        fixture.whenStable().then(() => {
           expect(document.querySelector('mat-dialog-container')).toBeNull();
           expect(testComponent.datepickerInput.value).toEqual(new Date(2020, JAN, 2));
-        });
-      });
+        }));
 
       it('clicking the currently selected date should close the calendar ' +
          'without firing selectedChanged', fakeAsync(() => {
@@ -1342,6 +1324,52 @@ describe('MatDatepicker', () => {
       expect(testComponent.datepickerInput.value).toBe(selected);
     }));
   });
+
+  describe('popup animations', () => {
+    let fixture: ComponentFixture<StandardDatepicker>;
+
+    beforeEach(fakeAsync(() => {
+      TestBed.configureTestingModule({
+        imports: [MatDatepickerModule, MatNativeDateModule, NoopAnimationsModule],
+        declarations: [StandardDatepicker],
+      }).compileComponents();
+
+      fixture = TestBed.createComponent(StandardDatepicker);
+      fixture.detectChanges();
+    }));
+
+    it('should not set the `mat-datepicker-content-above` class when opening downwards',
+      fakeAsync(() => {
+        fixture.componentInstance.datepicker.open();
+        fixture.detectChanges();
+        flush();
+        fixture.detectChanges();
+
+        const content =
+            document.querySelector('.cdk-overlay-pane mat-datepicker-content')! as HTMLElement;
+
+        expect(content.classList).not.toContain('mat-datepicker-content-above');
+      }));
+
+    it('should set the `mat-datepicker-content-above` class when opening upwards', fakeAsync(() => {
+      const input = fixture.debugElement.nativeElement.querySelector('input');
+
+      // Push the input to the bottom of the page to force the calendar to open upwards
+      input.style.position = 'fixed';
+      input.style.bottom = '0';
+
+      fixture.componentInstance.datepicker.open();
+      fixture.detectChanges();
+      flush();
+      fixture.detectChanges();
+
+      const content =
+          document.querySelector('.cdk-overlay-pane mat-datepicker-content')! as HTMLElement;
+
+      expect(content.classList).toContain('mat-datepicker-content-above');
+    }));
+
+  });
 });
 
 

src/lib/datepicker/datepicker.ts

@@ -16,6 +16,7 @@ import {
   PositionStrategy,
   RepositionScrollStrategy,
   ScrollStrategy,
+  ConnectedPositionStrategy,
 } from '@angular/cdk/overlay';
 import {ComponentPortal} from '@angular/cdk/portal';
 import {take} from 'rxjs/operators/take';
@@ -37,6 +38,8 @@ import {
   ViewChild,
   ViewContainerRef,
   ViewEncapsulation,
+  ChangeDetectorRef,
+  OnInit,
 } from '@angular/core';
 import {CanColor, DateAdapter, mixinColor, ThemePalette} from '@angular/material/core';
 import {MatDialog, MatDialogRef} from '@angular/material/dialog';
@@ -47,7 +50,7 @@ import {merge} from 'rxjs/observable/merge';
 import {createMissingDateImplError} from './datepicker-errors';
 import {MatDatepickerInput} from './datepicker-input';
 import {MatCalendar} from './calendar';
-
+import {matDatepickerAnimations} from './datepicker-animations';
 
 /** Used to generate a unique ID for each datepicker instance. */
 let datepickerUid = 0;
@@ -90,23 +93,61 @@ export const _MatDatepickerContentMixinBase = mixinColor(MatDatepickerContentBas
   styleUrls: ['datepicker-content.css'],
   host: {
     'class': 'mat-datepicker-content',
+    '[@transformPanel]': '"enter"',
     '[class.mat-datepicker-content-touch]': 'datepicker.touchUi',
+    '[class.mat-datepicker-content-above]': '_isAbove',
   },
+  animations: [
+    matDatepickerAnimations.transformPanel,
+    matDatepickerAnimations.fadeInCalendar,
+  ],
   exportAs: 'matDatepickerContent',
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush,
   inputs: ['color'],
 })
 export class MatDatepickerContent<D> extends _MatDatepickerContentMixinBase
-  implements AfterContentInit, CanColor {
-  datepicker: MatDatepicker<D>;
+  implements AfterContentInit, CanColor, OnInit, OnDestroy {
 
+  /** Subscription to changes in the overlay's position. */
+  private _positionChange: Subscription|null;
+
+  /** Reference to the internal calendar component. */
   @ViewChild(MatCalendar) _calendar: MatCalendar<D>;
 
-  constructor(elementRef: ElementRef, private _ngZone: NgZone) {
+  /** Reference to the datepicker that created the overlay. */
+  datepicker: MatDatepicker<D>;
+
+  /** Whether the datepicker is above or below the input. */
+  _isAbove: boolean;
+
+  constructor(
+    elementRef: ElementRef,
+    private _changeDetectorRef: ChangeDetectorRef,
+    private _ngZone: NgZone) {
     super(elementRef);
   }
 
+  ngOnInit() {
+    if (!this.datepicker._popupRef || this._positionChange) {
+      return;
+    }
+
+    const positionStrategy =
+      this.datepicker._popupRef.getConfig().positionStrategy! as ConnectedPositionStrategy;
+
+    this._positionChange = positionStrategy.onPositionChange.subscribe(change => {
+      const isAbove = change.connectionPair.overlayY === 'bottom';
+
+      if (isAbove !== this._isAbove) {
+        this._ngZone.run(() => {
+          this._isAbove = isAbove;
+          this._changeDetectorRef.markForCheck();
+        });
+      }
+    });
+  }
+
   ngAfterContentInit() {
     this._focusActiveCell();
   }
@@ -119,6 +160,13 @@ export class MatDatepickerContent<D> extends _MatDatepickerContentMixinBase
       });
     });
   }
+
+  ngOnDestroy() {
+    if (this._positionChange) {
+      this._positionChange.unsubscribe();
+      this._positionChange = null;
+    }
+  }
 }
 
 
@@ -246,7 +294,7 @@ export class MatDatepicker<D> implements OnDestroy, CanColor {
   }
 
   /** A reference to the overlay when the calendar is opened as a popup. */
-  private _popupRef: OverlayRef;
+  _popupRef: OverlayRef;
 
   /** A reference to the dialog when the calendar is opened as a dialog. */
   private _dialogRef: MatDialogRef<MatDatepickerContent<D>> | null;

src/lib/datepicker/public-api.ts

@@ -10,9 +10,9 @@ export * from './datepicker-module';
 export * from './calendar';
 export * from './calendar-body';
 export * from './datepicker';
+export * from './datepicker-animations';
 export * from './datepicker-input';
 export * from './datepicker-intl';
 export * from './datepicker-toggle';
 export * from './month-view';
 export * from './year-view';
-