feat(cdk/menu): add backdrop options to context menu and menu trigger

Currently, we do not have backdrop option for cdk menu. This change will add the those features.

Fixes #31399

Author: mistrykaran91

src/cdk/menu/context-menu-trigger.spec.ts

@@ -1,5 +1,5 @@
 import {Component, ViewChild, ElementRef, ViewChildren, QueryList} from '@angular/core';
-import {TestBed, ComponentFixture} from '@angular/core/testing';
+import {TestBed, ComponentFixture, fakeAsync, tick} from '@angular/core/testing';
 import {CdkMenu} from './menu';
 import {CdkContextMenuTrigger} from './context-menu-trigger';
 import {dispatchKeyboardEvent, dispatchMouseEvent} from '../testing/private';
@@ -8,6 +8,8 @@ import {CdkMenuItem} from './menu-item';
 import {CdkMenuTrigger} from './menu-trigger';
 import {CdkMenuBar} from './menu-bar';
 import {LEFT_ARROW, RIGHT_ARROW} from '../keycodes';
+import {OverlayContainer} from '../overlay';
+import {CDK_MENU_DEFAULT_OPTIONS} from './menu-trigger-base';
 
 describe('CdkContextMenuTrigger', () => {
   describe('with simple context menu trigger', () => {
@@ -380,6 +382,77 @@ describe('CdkContextMenuTrigger', () => {
     });
   });
 
+  describe('with backdrop in options', () => {
+    let fixture: ComponentFixture<SimpleContextMenu>;
+    let overlayContainerElement: HTMLElement;
+
+    beforeEach(() => {
+      fixture = TestBed.createComponent(SimpleContextMenu);
+      fixture.detectChanges();
+    });
+
+    /** Get the context in which the context menu should trigger. */
+    function getMenuTrigger() {
+      return fixture.componentInstance.triggerElement.nativeElement;
+    }
+
+    /** Open up the context menu and run change detection. */
+    function openContextMenu() {
+      // right click triggers a context menu event
+      dispatchMouseEvent(getMenuTrigger(), 'contextmenu');
+      fixture.detectChanges();
+    }
+
+    it('should not contain backdrop by default', fakeAsync(() => {
+      openContextMenu();
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      fixture.detectChanges();
+      tick(500);
+      expect(overlayContainerElement.querySelector('.cdk-overlay-backdrop')).toBeFalsy();
+    }));
+
+    it('should be able to add the backdrop using hasBackdrop option', fakeAsync(() => {
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [{provide: CDK_MENU_DEFAULT_OPTIONS, useValue: {hasBackdrop: true}}],
+      });
+
+      fixture = TestBed.createComponent(SimpleContextMenu);
+      fixture.detectChanges();
+
+      openContextMenu();
+
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      fixture.detectChanges();
+      tick(500);
+
+      expect(overlayContainerElement.querySelector('.cdk-overlay-backdrop')).toBeTruthy();
+    }));
+
+    it('should be able to add the custom backdrop class using backdropClass option', fakeAsync(() => {
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [
+          {
+            provide: CDK_MENU_DEFAULT_OPTIONS,
+            useValue: {hasBackdrop: true, backdropClass: 'custom-backdrop'},
+          },
+        ],
+      });
+
+      fixture = TestBed.createComponent(SimpleContextMenu);
+      fixture.detectChanges();
+
+      openContextMenu();
+
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      fixture.detectChanges();
+      tick(500);
+
+      expect(overlayContainerElement.querySelector('.custom-backdrop')).toBeTruthy();
+    }));
+  });
+
   describe('with shared triggered menu', () => {
     it('should allow a context menu and menubar trigger share a menu', () => {
       const fixture = TestBed.createComponent(MenuBarAndContextTriggerShareMenu);

src/cdk/menu/context-menu-trigger.ts

@@ -27,7 +27,14 @@ import {_getEventTarget} from '../platform';
 import {merge, partition} from 'rxjs';
 import {skip, takeUntil, skipWhile} from 'rxjs/operators';
 import {MENU_STACK, MenuStack} from './menu-stack';
-import {CdkMenuTriggerBase, MENU_TRIGGER, MenuTracker} from './menu-trigger-base';
+import {
+  CDK_MENU_DEFAULT_OPTIONS,
+  CdkMenuDefaultOptions,
+  CdkMenuTriggerBase,
+  MENU_TRIGGER,
+  MenuTracker,
+} from './menu-trigger-base';
+import {coerceArray} from '../coercion';
 
 /** The preferred menu positions for the context menu. */
 const CONTEXT_MENU_POSITIONS = STANDARD_DROPDOWN_BELOW_POSITIONS.map(position => {
@@ -78,6 +85,13 @@ export class CdkContextMenuTrigger extends CdkMenuTriggerBase implements OnDestr
 
   private readonly _changeDetectorRef = inject(ChangeDetectorRef);
 
+  private _defaults = inject<CdkMenuDefaultOptions | null>(CDK_MENU_DEFAULT_OPTIONS, {
+    optional: true,
+  });
+
+  /** Classes to apply to the panel. */
+  readonly _overlayPanelClass = coerceArray(this._defaults?.overlayPanelClass || []);
+
   /** Whether the context menu is disabled. */
   @Input({alias: 'cdkContextMenuDisabled', transform: booleanAttribute}) disabled: boolean = false;
 
@@ -137,6 +151,11 @@ export class CdkContextMenuTrigger extends CdkMenuTriggerBase implements OnDestr
       positionStrategy: this._getOverlayPositionStrategy(coordinates),
       scrollStrategy: this.menuScrollStrategy(),
       direction: this._directionality || undefined,
+      ...(this.menuStack.isEmpty() && {
+        hasBackdrop: this._defaults?.hasBackdrop,
+        panelClass: this._overlayPanelClass,
+        backdropClass: this._defaults?.backdropClass || 'cdk-overlay-transparent-backdrop',
+      }),
     });
   }
 

src/cdk/menu/menu-trigger-base.ts

@@ -43,6 +43,29 @@ export const MENU_SCROLL_STRATEGY = new InjectionToken<() => ScrollStrategy>(
   },
 );
 
+/** Default `cdk-menu` options that can be overridden. */
+export interface CdkMenuDefaultOptions {
+  /** Class to be applied to the menu's backdrop. */
+  backdropClass?: string;
+
+  /** Whether the menu has a backdrop. */
+  hasBackdrop?: boolean;
+
+  /** Class or list of classes to be applied to the menu's overlay panel. */
+  overlayPanelClass?: string | string[];
+}
+
+/** Injection token to be used to override the default options for `cdk-menu`. */
+export const CDK_MENU_DEFAULT_OPTIONS = new InjectionToken<CdkMenuDefaultOptions>(
+  'cdk-menu-default-options',
+  {
+    providedIn: 'root',
+    factory: () => ({
+      hasBackdrop: false,
+    }),
+  },
+);
+
 /** Tracks the last open menu trigger across the entire application. */
 @Injectable({providedIn: 'root'})
 export class MenuTracker {

src/cdk/menu/menu-trigger.spec.ts

@@ -8,6 +8,8 @@ import {Menu} from './menu-interface';
 import {CdkMenuItem} from './menu-item';
 import {CdkMenuTrigger} from './menu-trigger';
 import {CdkMenuBar} from './menu-bar';
+import {OverlayContainer} from '../overlay';
+import {CDK_MENU_DEFAULT_OPTIONS} from './menu-trigger-base';
 
 describe('MenuTrigger', () => {
   describe('on CdkMenuItem', () => {
@@ -515,6 +517,65 @@ describe('MenuTrigger', () => {
     });
   });
 
+  describe('with backdrop in options', () => {
+    let overlayContainerElement: HTMLElement;
+
+    it('should not contain backdrop by default', fakeAsync(() => {
+      const fixture = TestBed.createComponent(MenuBarWithNestedSubMenus);
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      fixture.detectChanges();
+
+      const triggers = fixture.componentInstance.triggers.toArray();
+      triggers[0].toggle();
+      fixture.detectChanges();
+
+      tick(500);
+
+      expect(overlayContainerElement.querySelector('.cdk-overlay-backdrop')).toBeFalsy();
+    }));
+
+    it('should be able to add the backdrop using hasBackdrop option', fakeAsync(() => {
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [{provide: CDK_MENU_DEFAULT_OPTIONS, useValue: {hasBackdrop: true}}],
+      });
+
+      const fixture = TestBed.createComponent(MenuBarWithNestedSubMenus);
+      fixture.detectChanges();
+
+      const triggers = fixture.componentInstance.triggers.toArray();
+      triggers[0].toggle();
+      fixture.detectChanges();
+
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      tick(500);
+      expect(overlayContainerElement.querySelector('.cdk-overlay-backdrop')).toBeTruthy();
+    }));
+
+    it('should be able to add the custom backdrop class using backdropClass option', fakeAsync(() => {
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [
+          {
+            provide: CDK_MENU_DEFAULT_OPTIONS,
+            useValue: {hasBackdrop: true, backdropClass: 'custom-backdrop'},
+          },
+        ],
+      });
+
+      const fixture = TestBed.createComponent(MenuBarWithNestedSubMenus);
+      fixture.detectChanges();
+      const triggers = fixture.componentInstance.triggers.toArray();
+      triggers[0].toggle();
+      fixture.detectChanges();
+
+      overlayContainerElement = TestBed.inject(OverlayContainer).getContainerElement();
+      tick(500);
+
+      expect(overlayContainerElement.querySelector('.custom-backdrop')).toBeTruthy();
+    }));
+  });
+
   it('should focus the first item when opening on click', fakeAsync(() => {
     const fixture = TestBed.createComponent(TriggersWithSameMenuDifferentMenuBars);
     fixture.detectChanges();

src/cdk/menu/menu-trigger.ts

@@ -43,8 +43,15 @@ import {takeUntil} from 'rxjs/operators';
 import {CDK_MENU, Menu} from './menu-interface';
 import {PARENT_OR_NEW_MENU_STACK_PROVIDER} from './menu-stack';
 import {MENU_AIM} from './menu-aim';
-import {CdkMenuTriggerBase, MENU_TRIGGER, MenuTracker} from './menu-trigger-base';
+import {
+  CDK_MENU_DEFAULT_OPTIONS,
+  CdkMenuDefaultOptions,
+  CdkMenuTriggerBase,
+  MENU_TRIGGER,
+  MenuTracker,
+} from './menu-trigger-base';
 import {eventDispatchesNativeClick} from './event-detection';
+import {coerceArray} from '../coercion';
 
 /**
  * A directive that turns its host element into a trigger for a popup menu.
@@ -86,6 +93,13 @@ export class CdkMenuTrigger extends CdkMenuTriggerBase implements OnChanges, OnD
   private readonly _injector = inject(Injector);
   private _cleanupMouseenter: () => void;
 
+  private _defaults = inject<CdkMenuDefaultOptions | null>(CDK_MENU_DEFAULT_OPTIONS, {
+    optional: true,
+  });
+
+  /** Classes to apply to the panel. */
+  readonly _overlayPanelClass = coerceArray(this._defaults?.overlayPanelClass || []);
+
   /** The app's menu tracking registry */
   private readonly _menuTracker = inject(MenuTracker);
 
@@ -276,6 +290,11 @@ export class CdkMenuTrigger extends CdkMenuTriggerBase implements OnChanges, OnD
       positionStrategy: this._getOverlayPositionStrategy(),
       scrollStrategy: this.menuScrollStrategy(),
       direction: this._directionality || undefined,
+      ...(this.menuStack.isEmpty() && {
+        hasBackdrop: this._defaults?.hasBackdrop,
+        panelClass: this._overlayPanelClass,
+        backdropClass: this._defaults?.backdropClass || 'cdk-overlay-transparent-backdrop',
+      }),
     });
   }