diff --git a/goldens/cdk/menu/index.api.md b/goldens/cdk/menu/index.api.md
index 318e551c75c2..0bb19d86f117 100644
--- a/goldens/cdk/menu/index.api.md
+++ b/goldens/cdk/menu/index.api.md
@@ -235,7 +235,7 @@ export abstract class CdkMenuTriggerBase implements OnDestroy {
     abstract close(): void;
     readonly closed: EventEmitter<void>;
     protected readonly destroyed: Subject<void>;
-    protected getMenuContentPortal(): TemplatePortal<any>;
+    protected getMenuContentPortal(): TemplatePortal<any> | undefined;
     readonly injector: Injector;
     protected isElementInsideMenuStack(element: Element): boolean;
     isOpen(): boolean;
diff --git a/goldens/cdk/overlay/index.api.md b/goldens/cdk/overlay/index.api.md
index 5f83c88501c8..e5c474f19cbf 100644
--- a/goldens/cdk/overlay/index.api.md
+++ b/goldens/cdk/overlay/index.api.md
@@ -419,7 +419,7 @@ export interface OverlayConnectionPosition {
 export class OverlayContainer implements OnDestroy {
     constructor(...args: unknown[]);
     // (undocumented)
-    protected _containerElement: HTMLElement;
+    protected _containerElement: HTMLElement | undefined;
     protected _createContainer(): void;
     // (undocumented)
     protected _document: Document;
diff --git a/src/cdk/a11y/focus-monitor/focus-monitor.ts b/src/cdk/a11y/focus-monitor/focus-monitor.ts
index 948d0b78cf87..7d23d712b828 100644
--- a/src/cdk/a11y/focus-monitor/focus-monitor.ts
+++ b/src/cdk/a11y/focus-monitor/focus-monitor.ts
@@ -93,16 +93,16 @@ export class FocusMonitor implements OnDestroy {
   private _origin: FocusOrigin = null;
 
   /** The FocusOrigin of the last focus event tracked by the FocusMonitor. */
-  private _lastFocusOrigin: FocusOrigin;
+  private _lastFocusOrigin: FocusOrigin = null;
 
   /** Whether the window has just been focused. */
   private _windowFocused = false;
 
   /** The timeout id of the window focus timeout. */
-  private _windowFocusTimeoutId: ReturnType<typeof setTimeout>;
+  private _windowFocusTimeoutId: ReturnType<typeof setTimeout> | undefined;
 
   /** The timeout id of the origin clearing timeout. */
-  private _originTimeoutId: ReturnType<typeof setTimeout>;
+  private _originTimeoutId: ReturnType<typeof setTimeout> | undefined;
 
   /**
    * Whether the origin was determined via a touch interaction. Necessary as properly attributing
@@ -617,7 +617,7 @@ export class CdkMonitorFocus implements AfterViewInit, OnDestroy {
   private _elementRef = inject<ElementRef<HTMLElement>>(ElementRef);
   private _focusMonitor = inject(FocusMonitor);
 
-  private _monitorSubscription: Subscription;
+  private _monitorSubscription: Subscription | undefined;
   private _focusOrigin: FocusOrigin = null;
 
   @Output() readonly cdkFocusChange = new EventEmitter<FocusOrigin>();
@@ -641,9 +641,6 @@ export class CdkMonitorFocus implements AfterViewInit, OnDestroy {
 
   ngOnDestroy() {
     this._focusMonitor.stopMonitoring(this._elementRef);
-
-    if (this._monitorSubscription) {
-      this._monitorSubscription.unsubscribe();
-    }
+    this._monitorSubscription?.unsubscribe();
   }
 }
diff --git a/src/cdk/a11y/focus-trap/focus-trap.ts b/src/cdk/a11y/focus-trap/focus-trap.ts
index 225410192f8b..9e9f44ea76b0 100644
--- a/src/cdk/a11y/focus-trap/focus-trap.ts
+++ b/src/cdk/a11y/focus-trap/focus-trap.ts
@@ -36,8 +36,8 @@ import {_CdkPrivateStyleLoader, _VisuallyHiddenLoader} from '../../private';
  * Things like `tabIndex > 0`, flex `order`, and shadow roots can cause the two to be misaligned.
  */
 export class FocusTrap {
-  private _startAnchor: HTMLElement | null;
-  private _endAnchor: HTMLElement | null;
+  private _startAnchor: HTMLElement | null = null;
+  private _endAnchor: HTMLElement | null = null;
   private _hasAttached = false;
 
   // Event listeners for the anchors. Need to be regular functions so that we can unbind them later.
@@ -413,7 +413,7 @@ export class CdkTrapFocus implements OnDestroy, AfterContentInit, OnChanges, DoC
   private _focusTrapFactory = inject(FocusTrapFactory);
 
   /** Underlying FocusTrap instance. */
-  focusTrap: FocusTrap;
+  focusTrap: FocusTrap = undefined!;
 
   /** Previously focused element to restore focus to upon destroy when using autoCapture. */
   private _previouslyFocusedElement: HTMLElement | null = null;
@@ -433,7 +433,8 @@ export class CdkTrapFocus implements OnDestroy, AfterContentInit, OnChanges, DoC
    * Whether the directive should automatically move focus into the trapped region upon
    * initialization and return focus to the previous activeElement upon destruction.
    */
-  @Input({alias: 'cdkTrapFocusAutoCapture', transform: booleanAttribute}) autoCapture: boolean;
+  @Input({alias: 'cdkTrapFocusAutoCapture', transform: booleanAttribute})
+  autoCapture: boolean = false;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/a11y/high-contrast-mode/high-contrast-mode-detector.ts b/src/cdk/a11y/high-contrast-mode/high-contrast-mode-detector.ts
index dbcdfa1de28f..6595ee81fd57 100644
--- a/src/cdk/a11y/high-contrast-mode/high-contrast-mode-detector.ts
+++ b/src/cdk/a11y/high-contrast-mode/high-contrast-mode-detector.ts
@@ -47,7 +47,7 @@ export class HighContrastModeDetector implements OnDestroy {
    * Figuring out the high contrast mode and adding the body classes can cause
    * some expensive layouts. This flag is used to ensure that we only do it once.
    */
-  private _hasCheckedHighContrastMode: boolean;
+  private _hasCheckedHighContrastMode = false;
   private _document = inject(DOCUMENT);
   private _breakpointSubscription: Subscription;
 
diff --git a/src/cdk/a11y/key-manager/list-key-manager.ts b/src/cdk/a11y/key-manager/list-key-manager.ts
index f2f9b398e462..8e5b8ad5a10f 100644
--- a/src/cdk/a11y/key-manager/list-key-manager.ts
+++ b/src/cdk/a11y/key-manager/list-key-manager.ts
@@ -45,7 +45,7 @@ export class ListKeyManager<T extends ListKeyManagerOption> {
   private _typeaheadSubscription = Subscription.EMPTY;
   private _itemChangesSubscription?: Subscription;
   private _vertical = true;
-  private _horizontal: 'ltr' | 'rtl' | null;
+  private _horizontal: 'ltr' | 'rtl' | null = null;
   private _allowedModifierKeys: ListKeyManagerModifierKey[] = [];
   private _homeAndEnd = false;
   private _pageUpAndDown = {enabled: false, delta: 10};
diff --git a/src/cdk/a11y/live-announcer/live-announcer.ts b/src/cdk/a11y/live-announcer/live-announcer.ts
index 2005f9ee4406..355e99c9b33f 100644
--- a/src/cdk/a11y/live-announcer/live-announcer.ts
+++ b/src/cdk/a11y/live-announcer/live-announcer.ts
@@ -43,7 +43,7 @@ export class LiveAnnouncer implements OnDestroy {
   private _liveElement: HTMLElement;
   private _document = inject(DOCUMENT);
   private _sanitizer = inject(DomSanitizer);
-  private _previousTimeout: ReturnType<typeof setTimeout>;
+  private _previousTimeout: ReturnType<typeof setTimeout> | undefined;
   private _currentPromise: Promise<void> | undefined;
   private _currentResolve: (() => void) | undefined;
 
@@ -250,7 +250,7 @@ export class CdkAriaLive implements OnDestroy {
     if (this._politeness === 'off') {
       if (this._subscription) {
         this._subscription.unsubscribe();
-        this._subscription = null;
+        this._subscription = undefined;
       }
     } else if (!this._subscription) {
       this._subscription = this._ngZone.runOutsideAngular(() => {
@@ -271,10 +271,10 @@ export class CdkAriaLive implements OnDestroy {
   private _politeness: AriaLivePoliteness = 'polite';
 
   /** Time in milliseconds after which to clear out the announcer element. */
-  @Input('cdkAriaLiveDuration') duration: number;
+  @Input('cdkAriaLiveDuration') duration!: number;
 
   private _previousAnnouncedText?: string;
-  private _subscription: Subscription | null;
+  private _subscription: Subscription | undefined;
 
   constructor(...args: unknown[]);
 
@@ -283,8 +283,6 @@ export class CdkAriaLive implements OnDestroy {
   }
 
   ngOnDestroy() {
-    if (this._subscription) {
-      this._subscription.unsubscribe();
-    }
+    this._subscription?.unsubscribe();
   }
 }
diff --git a/src/cdk/bidi/dir.ts b/src/cdk/bidi/dir.ts
index 20c1874718f3..ae85f8e21266 100644
--- a/src/cdk/bidi/dir.ts
+++ b/src/cdk/bidi/dir.ts
@@ -35,7 +35,7 @@ export class Dir implements Directionality, AfterContentInit, OnDestroy {
   private _isInitialized: boolean = false;
 
   /** Direction as passed in by the consumer. */
-  _rawDir: string;
+  _rawDir: string = '';
 
   /** Event emitted when the direction changes. */
   @Output('dirChange') readonly change = new EventEmitter<Direction>();
diff --git a/src/cdk/bidi/directionality.spec.ts b/src/cdk/bidi/directionality.spec.ts
index 295f292bfa05..f21993819f25 100644
--- a/src/cdk/bidi/directionality.spec.ts
+++ b/src/cdk/bidi/directionality.spec.ts
@@ -170,7 +170,7 @@ class InjectsDirectionality {
   imports: [Dir, InjectsDirectionality],
 })
 class ElementWithDir {
-  @ViewChild(Dir) dir: Dir;
+  @ViewChild(Dir) dir!: Dir;
   direction = signal<Direction>('rtl');
   changeCount = 0;
 }
@@ -180,7 +180,7 @@ class ElementWithDir {
   imports: [Dir],
 })
 class ElementWithPredefinedAutoDir {
-  @ViewChild(Dir) dir: Dir;
+  @ViewChild(Dir) dir!: Dir;
 }
 
 @Component({
@@ -188,7 +188,7 @@ class ElementWithPredefinedAutoDir {
   imports: [Dir],
 })
 class ElementWithPredefinedUppercaseDir {
-  @ViewChild(Dir) dir: Dir;
+  @ViewChild(Dir) dir!: Dir;
 }
 
 interface FakeDocument {
diff --git a/src/cdk/clipboard/copy-to-clipboard.ts b/src/cdk/clipboard/copy-to-clipboard.ts
index 4a74f7d69b94..d0fb44cc2421 100644
--- a/src/cdk/clipboard/copy-to-clipboard.ts
+++ b/src/cdk/clipboard/copy-to-clipboard.ts
@@ -63,7 +63,7 @@ export class CdkCopyToClipboard implements OnDestroy {
   private _pending = new Set<PendingCopy>();
 
   /** Whether the directive has been destroyed. */
-  private _destroyed: boolean;
+  private _destroyed = false;
 
   /** Timeout for the current copy attempt. */
   private _currentTimeout: any;
diff --git a/src/cdk/collections/selection-model.ts b/src/cdk/collections/selection-model.ts
index 3519e9d5dc76..0b6c0eb0f36f 100644
--- a/src/cdk/collections/selection-model.ts
+++ b/src/cdk/collections/selection-model.ts
@@ -22,7 +22,7 @@ export class SelectionModel<T> {
   private _selectedToEmit: T[] = [];
 
   /** Cache for the array value of the selected items. */
-  private _selected: T[] | null;
+  private _selected: T[] | null = null;
 
   /** Selected values. */
   get selected(): T[] {
diff --git a/src/cdk/dialog/dialog-container.ts b/src/cdk/dialog/dialog-container.ts
index c9b33c7b91f6..5ef4296b59e5 100644
--- a/src/cdk/dialog/dialog-container.ts
+++ b/src/cdk/dialog/dialog-container.ts
@@ -87,7 +87,7 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
   protected _document = inject(DOCUMENT);
 
   /** The portal outlet inside of this container into which the dialog content will be loaded. */
-  @ViewChild(CdkPortalOutlet, {static: true}) _portalOutlet: CdkPortalOutlet;
+  @ViewChild(CdkPortalOutlet, {static: true}) _portalOutlet!: CdkPortalOutlet;
 
   _focusTrapped: Observable<void> = new Subject<void>();
 
diff --git a/src/cdk/dialog/dialog-ref.ts b/src/cdk/dialog/dialog-ref.ts
index 8794605f3fe7..8aabefff4b42 100644
--- a/src/cdk/dialog/dialog-ref.ts
+++ b/src/cdk/dialog/dialog-ref.ts
@@ -27,16 +27,16 @@ export class DialogRef<R = unknown, C = unknown> {
    * Instance of component opened into the dialog. Will be
    * null when the dialog is opened using a `TemplateRef`.
    */
-  readonly componentInstance: C | null;
+  readonly componentInstance: C | null = null;
 
   /**
    * `ComponentRef` of the component opened into the dialog. Will be
    * null when the dialog is opened using a `TemplateRef`.
    */
-  readonly componentRef: ComponentRef<C> | null;
+  readonly componentRef: ComponentRef<C> | null = null;
 
   /** Instance of the container that is rendering out the dialog content. */
-  readonly containerInstance: DialogContainer;
+  readonly containerInstance!: DialogContainer;
 
   /** Whether the user is allowed to close the dialog. */
   disableClose: boolean | undefined;
diff --git a/src/cdk/drag-drop/directives/drag-placeholder.ts b/src/cdk/drag-drop/directives/drag-placeholder.ts
index e1ffb272c589..7f9a916a0b56 100644
--- a/src/cdk/drag-drop/directives/drag-placeholder.ts
+++ b/src/cdk/drag-drop/directives/drag-placeholder.ts
@@ -30,7 +30,7 @@ export class CdkDragPlaceholder<T = any> implements OnDestroy {
   private _drag = inject(CDK_DRAG_PARENT, {optional: true});
 
   /** Context data to be added to the placeholder template instance. */
-  @Input() data: T;
+  @Input() data!: T;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/drag-drop/directives/drag-preview.ts b/src/cdk/drag-drop/directives/drag-preview.ts
index bd7674e0668a..10131d5b4ff8 100644
--- a/src/cdk/drag-drop/directives/drag-preview.ts
+++ b/src/cdk/drag-drop/directives/drag-preview.ts
@@ -38,7 +38,7 @@ export class CdkDragPreview<T = any> implements OnDestroy {
   private _drag = inject(CDK_DRAG_PARENT, {optional: true});
 
   /** Context data to be added to the preview template instance. */
-  @Input() data: T;
+  @Input() data!: T;
 
   /** Whether the preview should preserve the same size as the item that is being dragged. */
   @Input({transform: booleanAttribute}) matchSize: boolean = false;
diff --git a/src/cdk/drag-drop/directives/drag.ts b/src/cdk/drag-drop/directives/drag.ts
index 436b9935943f..679b4ef2baba 100644
--- a/src/cdk/drag-drop/directives/drag.ts
+++ b/src/cdk/drag-drop/directives/drag.ts
@@ -81,14 +81,14 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
 
   private readonly _destroyed = new Subject<void>();
   private _handles = new BehaviorSubject<CdkDragHandle[]>([]);
-  private _previewTemplate: CdkDragPreview | null;
-  private _placeholderTemplate: CdkDragPlaceholder | null;
+  private _previewTemplate: CdkDragPreview | null = null;
+  private _placeholderTemplate: CdkDragPlaceholder | null = null;
 
   /** Reference to the underlying drag instance. */
   _dragRef: DragRef<CdkDrag<T>>;
 
   /** Arbitrary data to attach to this drag instance. */
-  @Input('cdkDragData') data: T;
+  @Input('cdkDragData') data!: T;
 
   /** Locks the position of the dragged element along the specified axis. */
   @Input('cdkDragLockAxis') lockAxis: DragAxis | null = null;
@@ -98,7 +98,7 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
    * the `cdkDrag` element and going up the DOM. Passing an alternate root element is useful
    * when trying to enable dragging on an element that you might not have access to.
    */
-  @Input('cdkDragRootElement') rootElementSelector: string;
+  @Input('cdkDragRootElement') rootElementSelector!: string;
 
   /**
    * Node or selector that will be used to determine the element to which the draggable's
@@ -106,19 +106,19 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
    * will be matched starting from the element's parent and going up the DOM until a match
    * has been found.
    */
-  @Input('cdkDragBoundary') boundaryElement: string | ElementRef<HTMLElement> | HTMLElement;
+  @Input('cdkDragBoundary') boundaryElement!: string | ElementRef<HTMLElement> | HTMLElement;
 
   /**
    * Amount of milliseconds to wait after the user has put their
    * pointer down before starting to drag the element.
    */
-  @Input('cdkDragStartDelay') dragStartDelay: DragStartDelay;
+  @Input('cdkDragStartDelay') dragStartDelay!: DragStartDelay;
 
   /**
    * Sets the position of a `CdkDrag` that is outside of a drop container.
    * Can be used to restore the element's position for a returning user.
    */
-  @Input('cdkDragFreeDragPosition') freeDragPosition: Point;
+  @Input('cdkDragFreeDragPosition') freeDragPosition!: Point;
 
   /** Whether starting to drag this element is disabled. */
   @Input({alias: 'cdkDragDisabled', transform: booleanAttribute})
@@ -129,7 +129,7 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
     this._disabled = value;
     this._dragRef.disabled = this._disabled;
   }
-  private _disabled: boolean;
+  private _disabled = false;
 
   /**
    * Function that can be used to customize the logic of how the position of the drag item
@@ -140,7 +140,7 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
   @Input('cdkDragConstrainPosition') constrainPosition?: DragConstrainPosition;
 
   /** Class to be added to the preview element. */
-  @Input('cdkDragPreviewClass') previewClass: string | string[];
+  @Input('cdkDragPreviewClass') previewClass!: string | string[];
 
   /**
    * Configures the place into which the preview of the item will be inserted. Can be configured
@@ -155,7 +155,7 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
    * - `ElementRef<HTMLElement> | HTMLElement` - Preview will be inserted into a specific element.
    * Same advantages and disadvantages as `parent`.
    */
-  @Input('cdkDragPreviewContainer') previewContainer: PreviewContainer;
+  @Input('cdkDragPreviewContainer') previewContainer!: PreviewContainer;
 
   /**
    * If the parent of the dragged element has a `scale` transform, it can throw off the
diff --git a/src/cdk/drag-drop/directives/drop-list-shared.spec.ts b/src/cdk/drag-drop/directives/drop-list-shared.spec.ts
index a3ed399ffd21..dda1b75b16c3 100644
--- a/src/cdk/drag-drop/directives/drop-list-shared.spec.ts
+++ b/src/cdk/drag-drop/directives/drop-list-shared.spec.ts
@@ -5030,15 +5030,15 @@ export function getHorizontalFixtures(listOrientation: Exclude<DropListOrientati
   class DraggableInHorizontalDropZone implements AfterViewInit {
     readonly _elementRef = inject(ElementRef);
 
-    @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-    @ViewChild(CdkDropList) dropInstance: CdkDropList;
+    @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+    @ViewChild(CdkDropList) dropInstance!: CdkDropList;
     items = [
       {value: 'Zero', width: ITEM_WIDTH, margin: 0},
       {value: 'One', width: ITEM_WIDTH, margin: 0},
       {value: 'Two', width: ITEM_WIDTH, margin: 0},
       {value: 'Three', width: ITEM_WIDTH, margin: 0},
     ];
-    boundarySelector: string;
+    boundarySelector!: string;
     droppedSpy = jasmine.createSpy('dropped spy').and.callFake((event: CdkDragDrop<string[]>) => {
       moveItemInArray(this.items, event.previousIndex, event.currentIndex);
     });
@@ -5113,7 +5113,7 @@ export function getHorizontalFixtures(listOrientation: Exclude<DropListOrientati
     imports: [CdkDropList, CdkDrag, CdkDragPreview],
   })
   class DraggableInHorizontalFlexDropZoneWithMatchSizePreview {
-    @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+    @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
     items = ['Zero', 'One', 'Two'];
   }
 
@@ -5160,9 +5160,9 @@ const DROP_ZONE_FIXTURE_TEMPLATE = `
 export class DraggableInDropZone implements AfterViewInit {
   protected _elementRef = inject(ElementRef);
 
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
-  @ViewChild('alternatePreviewContainer') alternatePreviewContainer: ElementRef<HTMLElement>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
+  @ViewChild('alternatePreviewContainer') alternatePreviewContainer!: ElementRef<HTMLElement>;
   items = [
     {value: 'Zero', height: ITEM_HEIGHT, margin: 0},
     {value: 'One', height: ITEM_HEIGHT, margin: 0},
@@ -5170,8 +5170,8 @@ export class DraggableInDropZone implements AfterViewInit {
     {value: 'Three', height: ITEM_HEIGHT, margin: 0},
   ];
   dropZoneId = 'items';
-  boundarySelector: string;
-  previewClass: string | string[];
+  boundarySelector!: string;
+  previewClass: string | string[] = [];
   sortedSpy = jasmine.createSpy('sorted spy');
   droppedSpy = jasmine.createSpy('dropped spy').and.callFake((event: CdkDragDrop<string[]>) => {
     moveItemInArray(this.items, event.previousIndex, event.currentIndex);
@@ -5252,7 +5252,7 @@ export class DraggableInScrollableVerticalDropZone extends DraggableInDropZone {
   imports: [CdkDropList, CdkDrag, NgFor, CdkScrollable],
 })
 class DraggableInScrollableParentContainer extends DraggableInDropZone implements AfterViewInit {
-  @ViewChild('scrollContainer') scrollContainer: ElementRef<HTMLElement>;
+  @ViewChild('scrollContainer') scrollContainer!: ElementRef<HTMLElement>;
 
   constructor() {
     super();
@@ -5329,19 +5329,19 @@ class DraggableInDropZoneWithContainer extends DraggableInDropZone {}
   imports: [CdkDropList, CdkDrag, CdkDragPreview, NgIf],
 })
 class DraggableInDropZoneWithCustomPreview {
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items: {label: string; lockAxis?: DragAxis}[] = [
     {label: 'Zero'},
     {label: 'One'},
     {label: 'Two'},
     {label: 'Three'},
   ];
-  boundarySelector: string;
+  boundarySelector!: string;
   renderCustomPreview = true;
   matchPreviewSize = false;
-  previewClass: string | string[];
-  constrainPosition: (point: Point) => Point;
+  previewClass: string | string[] = [];
+  constrainPosition: ((point: Point) => Point) | undefined;
   dropLockAxis = signal<DragAxis | undefined>(undefined);
 }
 
@@ -5363,8 +5363,8 @@ class DraggableInDropZoneWithCustomPreview {
   imports: [CdkDropList, CdkDrag, CdkDragPreview],
 })
 class DraggableInDropZoneWithCustomTextOnlyPreview {
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -5385,8 +5385,8 @@ class DraggableInDropZoneWithCustomTextOnlyPreview {
   imports: [CdkDropList, CdkDrag, CdkDragPreview],
 })
 class DraggableInDropZoneWithCustomMultiNodePreview {
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -5417,7 +5417,7 @@ class DraggableInDropZoneWithCustomMultiNodePreview {
   imports: [CdkDropList, CdkDrag, CdkDragPlaceholder, NgClass],
 })
 class DraggableInDropZoneWithCustomPlaceholder {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = ['Zero', 'One', 'Two', 'Three'];
   renderPlaceholder = true;
   extraPlaceholderClass = '';
@@ -5438,7 +5438,7 @@ class DraggableInDropZoneWithCustomPlaceholder {
   imports: [CdkDropList, CdkDrag, CdkDragPlaceholder],
 })
 class DraggableInDropZoneWithCustomTextOnlyPlaceholder {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -5459,7 +5459,7 @@ class DraggableInDropZoneWithCustomTextOnlyPlaceholder {
   imports: [CdkDropList, CdkDrag, CdkDragPlaceholder],
 })
 class DraggableInDropZoneWithCustomMultiNodePlaceholder {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -5537,8 +5537,8 @@ const CONNECTED_DROP_ZONES_TEMPLATE = `
   imports: [CdkDropList, CdkDrag],
 })
 export class ConnectedDropZones implements AfterViewInit {
-  @ViewChildren(CdkDrag) rawDragItems: QueryList<CdkDrag>;
-  @ViewChildren(CdkDropList) dropInstances: QueryList<CdkDropList>;
+  @ViewChildren(CdkDrag) rawDragItems!: QueryList<CdkDrag>;
+  @ViewChildren(CdkDropList) dropInstances!: QueryList<CdkDropList>;
   changeDetectorRef = inject(ChangeDetectorRef);
 
   groupedDragItems: CdkDrag[][] = [];
@@ -5652,8 +5652,8 @@ class ConnectedDropZonesViaGroupDirective extends ConnectedDropZones {
   imports: [CdkDropList, CdkDrag],
 })
 class ConnectedDropZonesWithSingleItems {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChildren(CdkDropList) dropInstances: QueryList<CdkDropList>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChildren(CdkDropList) dropInstances!: QueryList<CdkDropList>;
 
   droppedSpy = jasmine.createSpy('dropped spy');
 }
@@ -5672,9 +5672,9 @@ class ConnectedDropZonesWithSingleItems {
   imports: [CdkDropList, CdkDropListGroup],
 })
 class NestedDropListGroups {
-  @ViewChild('group') group: CdkDropListGroup<CdkDropList>;
-  @ViewChild('listOne') listOne: CdkDropList;
-  @ViewChild('listTwo') listTwo: CdkDropList;
+  @ViewChild('group') group!: CdkDropListGroup<CdkDropList>;
+  @ViewChild('listOne') listOne!: CdkDropList;
+  @ViewChild('listTwo') listTwo!: CdkDropList;
 }
 
 @Component({
@@ -5700,8 +5700,8 @@ class DropListOnNgContainer {}
   `,
 })
 class DraggableInDropZoneWithoutEvents {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
   items = [
     {value: 'Zero', height: ITEM_HEIGHT},
     {value: 'One', height: ITEM_HEIGHT},
@@ -5724,7 +5724,7 @@ class DraggableInDropZoneWithoutEvents {
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 class WrappedDropContainerComponent {
-  @Input() items: string[];
+  @Input() items: string[] | undefined;
 }
 
 @Component({
@@ -5862,8 +5862,8 @@ class DraggableWithInvalidCanvasInDropZone extends DraggableInDropZone {}
   imports: [CdkDrag],
 })
 class NestedDragsComponent {
-  @ViewChild('container') container: ElementRef;
-  @ViewChild('item') item: ElementRef;
+  @ViewChild('container') container!: ElementRef;
+  @ViewChild('item') item!: ElementRef;
 
   containerDragStartedSpy = jasmine.createSpy('container drag started spy');
   containerDragMovedSpy = jasmine.createSpy('container drag moved spy');
@@ -5916,8 +5916,8 @@ class NestedDragsComponent {
   imports: [CdkDrag, NgTemplateOutlet],
 })
 class NestedDragsThroughTemplate {
-  @ViewChild('container') container: ElementRef;
-  @ViewChild('item') item: ElementRef;
+  @ViewChild('container') container!: ElementRef;
+  @ViewChild('item') item!: ElementRef;
 }
 
 @Component({
@@ -5941,9 +5941,9 @@ class NestedDragsThroughTemplate {
   imports: [CdkDropList, CdkDrag],
 })
 class NestedDropZones {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild('outerList') outerList: ElementRef<HTMLElement>;
-  @ViewChild('innerList') innerList: ElementRef<HTMLElement>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild('outerList') outerList!: ElementRef<HTMLElement>;
+  @ViewChild('innerList') innerList!: ElementRef<HTMLElement>;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -5952,7 +5952,7 @@ class NestedDropZones {
   imports: [CdkDropList],
 })
 class PlainStandaloneDropList {
-  @ViewChild(CdkDropList) dropList: CdkDropList;
+  @ViewChild(CdkDropList) dropList!: CdkDropList;
 }
 @Component({
   styles: CONNECTED_DROP_ZONES_STYLES,
@@ -6048,7 +6048,7 @@ class DraggableWithInputsInDropZone extends DraggableInDropZone {
   imports: [CdkDropList, CdkDrag],
 })
 class DraggableWithRadioInputsInDropZone {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
   items = [
     {id: 1, checked: false},
     {id: 2, checked: false},
@@ -6121,8 +6121,8 @@ class ConnectedDropZonesWithAlternateContainer extends ConnectedDropZones {
   imports: [CdkDropList, CdkDrag],
 })
 class DraggableWithInvalidAlternateContainer {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
 
@@ -6143,7 +6143,7 @@ class DraggableWithInvalidAlternateContainer {
   imports: [CdkDropList, CdkDrag],
 })
 class DraggableWithMissingAlternateContainer {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
   items = ['Zero', 'One', 'Two', 'Three'];
 }
diff --git a/src/cdk/drag-drop/directives/drop-list.ts b/src/cdk/drag-drop/directives/drop-list.ts
index 7049d55409d0..a1fc256c8a1a 100644
--- a/src/cdk/drag-drop/directives/drop-list.ts
+++ b/src/cdk/drag-drop/directives/drop-list.ts
@@ -66,7 +66,7 @@ export class CdkDropList<T = any> implements OnDestroy {
   private readonly _destroyed = new Subject<void>();
 
   /** Whether the element's scrollable parents have been resolved. */
-  private _scrollableParentsResolved: boolean;
+  private _scrollableParentsResolved = false;
 
   /** Keeps track of the drop lists that are currently on the page. */
   private static _dropLists: CdkDropList[] = [];
@@ -83,10 +83,10 @@ export class CdkDropList<T = any> implements OnDestroy {
   connectedTo: (CdkDropList | string)[] | CdkDropList | string = [];
 
   /** Arbitrary data to attach to this container. */
-  @Input('cdkDropListData') data: T;
+  @Input('cdkDropListData') data!: T;
 
   /** Direction in which the list is oriented. */
-  @Input('cdkDropListOrientation') orientation: DropListOrientation;
+  @Input('cdkDropListOrientation') orientation: DropListOrientation = 'vertical';
 
   /**
    * Unique ID for the drop zone. Can be used as a reference
@@ -109,11 +109,11 @@ export class CdkDropList<T = any> implements OnDestroy {
     // the user in a disabled state, so we also need to sync it as it's being set.
     this._dropListRef.disabled = this._disabled = value;
   }
-  private _disabled: boolean;
+  private _disabled = false;
 
   /** Whether sorting within this drop list is disabled. */
   @Input({alias: 'cdkDropListSortingDisabled', transform: booleanAttribute})
-  sortingDisabled: boolean;
+  sortingDisabled: boolean = false;
 
   /**
    * Function that is used to determine whether an item
@@ -128,7 +128,7 @@ export class CdkDropList<T = any> implements OnDestroy {
 
   /** Whether to auto-scroll the view when the user moves their pointer close to the edges. */
   @Input({alias: 'cdkDropListAutoScrollDisabled', transform: booleanAttribute})
-  autoScrollDisabled: boolean;
+  autoScrollDisabled: boolean = false;
 
   /** Number of pixels to scroll for each frame when auto-scrolling an element. */
   @Input('cdkDropListAutoScrollStep')
@@ -148,7 +148,7 @@ export class CdkDropList<T = any> implements OnDestroy {
    * </div>
    * ```
    */
-  @Input('cdkDropListElementContainer') elementContainerSelector: string | null;
+  @Input('cdkDropListElementContainer') elementContainerSelector: string | null = null;
 
   /**
    * By default when an item leaves its initial container, its placeholder will be transferred
@@ -162,7 +162,7 @@ export class CdkDropList<T = any> implements OnDestroy {
    * behavior in a drop list.
    */
   @Input({alias: 'cdkDropListHasAnchor', transform: booleanAttribute})
-  hasAnchor: boolean;
+  hasAnchor: boolean = false;
 
   /** Emits when the user drops an item inside the container. */
   @Output('cdkDropListDropped')
diff --git a/src/cdk/drag-drop/directives/mixed-drop-list.spec.ts b/src/cdk/drag-drop/directives/mixed-drop-list.spec.ts
index ae2f7b480a99..6049c69f33f1 100644
--- a/src/cdk/drag-drop/directives/mixed-drop-list.spec.ts
+++ b/src/cdk/drag-drop/directives/mixed-drop-list.spec.ts
@@ -134,8 +134,8 @@ function getSortedSiblings(item: Element) {
   imports: [CdkDropList, CdkDrag],
 })
 class DraggableInHorizontalWrappingDropZone {
-  @ViewChildren(CdkDrag) dragItems: QueryList<CdkDrag>;
-  @ViewChild(CdkDropList) dropInstance: CdkDropList;
+  @ViewChildren(CdkDrag) dragItems!: QueryList<CdkDrag>;
+  @ViewChild(CdkDropList) dropInstance!: CdkDropList;
   items = ['Zero', 'One', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven'];
   droppedSpy = jasmine.createSpy('dropped spy').and.callFake((event: CdkDragDrop<string[]>) => {
     moveItemInArray(this.items, event.previousIndex, event.currentIndex);
diff --git a/src/cdk/drag-drop/directives/standalone-drag.spec.ts b/src/cdk/drag-drop/directives/standalone-drag.spec.ts
index e8cf6bdcbd2b..51dce4d322d4 100644
--- a/src/cdk/drag-drop/directives/standalone-drag.spec.ts
+++ b/src/cdk/drag-drop/directives/standalone-drag.spec.ts
@@ -1876,19 +1876,21 @@ describe('Standalone CdkDrag', () => {
   imports: [CdkDrag],
 })
 class StandaloneDraggable {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
   startedSpy = jasmine.createSpy('started spy');
   endedSpy = jasmine.createSpy('ended spy');
   releasedSpy = jasmine.createSpy('released spy');
-  boundary: string | HTMLElement;
-  dragStartDelay: number | string | {touch: number; mouse: number};
-  constrainPosition: (
-    userPointerPosition: Point,
-    dragRef: DragRef,
-    dimensions: DOMRect,
-    pickupPositionInElement: Point,
-  ) => Point;
+  boundary: string | HTMLElement | undefined;
+  dragStartDelay: number | string | {touch: number; mouse: number} | undefined;
+  constrainPosition:
+    | ((
+        userPointerPosition: Point,
+        dragRef: DragRef,
+        dimensions: DOMRect,
+        pickupPositionInElement: Point,
+      ) => Point)
+    | undefined;
   freeDragPosition?: {x: number; y: number};
   dragDisabled = signal(false);
   dragLockAxis = signal<DragAxis | undefined>(undefined);
@@ -1903,8 +1905,8 @@ class StandaloneDraggable {
   imports: [CdkDrag],
 })
 class StandaloneDraggableWithOnPush {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
 }
 
 @Component({
@@ -1917,10 +1919,10 @@ class StandaloneDraggableWithOnPush {
   imports: [CdkDrag, CdkDragHandle],
 })
 class StandaloneDraggableWithHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('handleElement') handleElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
-  @ViewChild(CdkDragHandle) handleInstance: CdkDragHandle;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('handleElement') handleElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
+  @ViewChild(CdkDragHandle) handleInstance!: CdkDragHandle;
   draggingDisabled = false;
 }
 
@@ -1938,9 +1940,9 @@ class StandaloneDraggableWithHandle {
   imports: [CdkDrag, CdkDragHandle],
 })
 class StandaloneDraggableWithPreDisabledHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('handleElement') handleElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('handleElement') handleElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
   disableHandle = true;
 }
 
@@ -1958,8 +1960,8 @@ class StandaloneDraggableWithPreDisabledHandle {
   imports: [CdkDrag, CdkDragHandle],
 })
 class StandaloneDraggableWithDelayedHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('handleElement') handleElement: ElementRef<HTMLElement>;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('handleElement') handleElement!: ElementRef<HTMLElement>;
   showHandle = false;
 }
 
@@ -1989,8 +1991,8 @@ class PassthroughComponent {}
   imports: [CdkDrag, CdkDragHandle, PassthroughComponent],
 })
 class StandaloneDraggableWithIndirectHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('handleElement') handleElement: ElementRef<HTMLElement>;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('handleElement') handleElement!: ElementRef<HTMLElement>;
 }
 
 @Component({
@@ -2013,8 +2015,8 @@ class ShadowWrapper {}
   imports: [CdkDrag, CdkDragHandle, ShadowWrapper],
 })
 class StandaloneDraggableWithShadowInsideHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('handleChild') handleChild: ElementRef<HTMLElement>;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('handleChild') handleChild!: ElementRef<HTMLElement>;
 }
 
 @Component({
@@ -2038,8 +2040,8 @@ class StandaloneDraggableWithShadowInsideHandle {
   imports: [CdkDrag, CdkDragHandle],
 })
 class StandaloneDraggableWithMultipleHandles {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChildren(CdkDragHandle) handles: QueryList<CdkDragHandle>;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChildren(CdkDragHandle) handles!: QueryList<CdkDragHandle>;
 }
 
 @Component({
@@ -2055,10 +2057,10 @@ class StandaloneDraggableWithMultipleHandles {
   imports: [CdkDrag],
 })
 class DraggableWithAlternateRoot {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('dragRoot') dragRoot: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
-  rootElementSelector: string;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('dragRoot') dragRoot!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
+  rootElementSelector: string | undefined;
 }
 
 @Component({
@@ -2093,9 +2095,9 @@ class DragHandleOnNgContainer {}
   imports: [CdkDrag, CdkDragHandle],
 })
 class DraggableWithAlternateRootAndSelfHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild('dragRoot') dragRoot: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild('dragRoot') dragRoot!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
 }
 
 @Component({
@@ -2109,8 +2111,8 @@ class DraggableWithAlternateRootAndSelfHandle {
   imports: [CdkDrag],
 })
 class DraggableNgContainerWithAlternateRoot {
-  @ViewChild('dragRoot') dragRoot: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragRoot') dragRoot!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
 }
 
 @Component({
@@ -2118,7 +2120,7 @@ class DraggableNgContainerWithAlternateRoot {
   imports: [CdkDrag],
 })
 class PlainStandaloneDraggable {
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
 }
 
 @Component({
@@ -2135,7 +2137,7 @@ class PlainStandaloneDraggable {
   imports: [CdkDrag, CdkDragHandle, NgTemplateOutlet],
 })
 class StandaloneDraggableWithExternalTemplateHandle {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
 }
 
 @Component({
@@ -2149,10 +2151,10 @@ class StandaloneDraggableWithExternalTemplateHandle {
   imports: [CdkDrag],
 })
 class DragWithResizeableBoundary {
-  @ViewChild('boundaryElement') boundaryElement: ElementRef<HTMLElement>;
+  @ViewChild('boundaryElement') boundaryElement!: ElementRef<HTMLElement>;
 
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
 
   setBoundary(height: string, width: string) {
     this.boundaryElement.nativeElement.style.height = height;
diff --git a/src/cdk/drag-drop/directives/standalone-drag.zone.spec.ts b/src/cdk/drag-drop/directives/standalone-drag.zone.spec.ts
index 19fe5f7b2ce8..8e8512c8d29a 100644
--- a/src/cdk/drag-drop/directives/standalone-drag.zone.spec.ts
+++ b/src/cdk/drag-drop/directives/standalone-drag.zone.spec.ts
@@ -54,13 +54,13 @@ describe('Standalone CdkDrag Zone.js integration', () => {
   imports: [CdkDrag],
 })
 class StandaloneDraggable {
-  @ViewChild('dragElement') dragElement: ElementRef<HTMLElement>;
-  @ViewChild(CdkDrag) dragInstance: CdkDrag;
+  @ViewChild('dragElement') dragElement!: ElementRef<HTMLElement>;
+  @ViewChild(CdkDrag) dragInstance!: CdkDrag;
   startedSpy = jasmine.createSpy('started spy');
   endedSpy = jasmine.createSpy('ended spy');
   releasedSpy = jasmine.createSpy('released spy');
-  boundary: string | HTMLElement;
-  dragStartDelay: number | string | {touch: number; mouse: number};
-  constrainPosition: (point: Point) => Point;
-  freeDragPosition?: {x: number; y: number};
+  boundary: string | HTMLElement | undefined;
+  dragStartDelay: number | string | {touch: number; mouse: number} | undefined;
+  constrainPosition: ((point: Point) => Point) | undefined;
+  freeDragPosition: {x: number; y: number} | undefined;
 }
diff --git a/src/cdk/drag-drop/drag-ref.ts b/src/cdk/drag-drop/drag-ref.ts
index 63c83d0881af..83a0292d86ef 100644
--- a/src/cdk/drag-drop/drag-ref.ts
+++ b/src/cdk/drag-drop/drag-ref.ts
@@ -132,28 +132,28 @@ export class DragRef<T = any> {
   private _cleanupShadowRootSelectStart: (() => void) | undefined;
 
   /** Element displayed next to the user's pointer while the element is dragged. */
-  private _preview: PreviewRef | null;
+  private _preview: PreviewRef | null = null;
 
   /** Container into which to insert the preview. */
   private _previewContainer: PreviewContainer | undefined;
 
   /** Reference to the view of the placeholder element. */
-  private _placeholderRef: EmbeddedViewRef<any> | null;
+  private _placeholderRef: EmbeddedViewRef<any> | null = null;
 
   /** Element that is rendered instead of the draggable item while it is being sorted. */
-  private _placeholder: HTMLElement;
+  private _placeholder!: HTMLElement;
 
   /** Coordinates within the element at which the user picked up the element. */
-  private _pickupPositionInElement: Point;
+  private _pickupPositionInElement!: Point;
 
   /** Coordinates on the page at which the user picked up the element. */
-  private _pickupPositionOnPage: Point;
+  private _pickupPositionOnPage!: Point;
 
   /**
    * Marker node used to save the place in the DOM where the element was
    * picked up so that it can be restored at the end of the drag sequence.
    */
-  private _marker: Comment;
+  private _marker!: Comment;
 
   /**
    * Element indicating the position from which the item was picked up initially.
@@ -181,13 +181,13 @@ export class DragRef<T = any> {
   private _hasStartedDragging = signal(false);
 
   /** Whether the element has moved since the user started dragging it. */
-  private _hasMoved: boolean;
+  private _hasMoved = false;
 
   /** Drop container in which the DragRef resided when dragging began. */
-  private _initialContainer: DropListRef;
+  private _initialContainer!: DropListRef;
 
   /** Index at which the item started in its initial container. */
-  private _initialIndex: number;
+  private _initialIndex!: number;
 
   /** Cached positions of scrollable parent elements. */
   private _parentPositions: ParentPositionTracker;
@@ -202,30 +202,30 @@ export class DragRef<T = any> {
   }>();
 
   /** Keeps track of the direction in which the user is dragging along each axis. */
-  private _pointerDirectionDelta: {x: -1 | 0 | 1; y: -1 | 0 | 1};
+  private _pointerDirectionDelta!: {x: -1 | 0 | 1; y: -1 | 0 | 1};
 
   /** Pointer position at which the last change in the delta occurred. */
-  private _pointerPositionAtLastDirectionChange: Point;
+  private _pointerPositionAtLastDirectionChange!: Point;
 
   /** Position of the pointer at the last pointer event. */
-  private _lastKnownPointerPosition: Point;
+  private _lastKnownPointerPosition!: Point;
 
   /**
    * Root DOM node of the drag instance. This is the element that will
    * be moved around as the user is dragging.
    */
-  private _rootElement: HTMLElement;
+  private _rootElement!: HTMLElement;
 
   /**
    * Nearest ancestor SVG, relative to which coordinates are calculated if dragging SVGElement
    */
-  private _ownerSVGElement: SVGSVGElement | null;
+  private _ownerSVGElement: SVGSVGElement | null = null;
 
   /**
    * Inline style value of `-webkit-tap-highlight-color` at the time the
    * dragging was started. Used to restore the value once we're done dragging.
    */
-  private _rootElementTapHighlight: string;
+  private _rootElementTapHighlight!: string;
 
   /** Subscription to pointer movement events. */
   private _pointerMoveSubscription = Subscription.EMPTY;
@@ -244,10 +244,10 @@ export class DragRef<T = any> {
    * events multiple times on touch devices where the browser will fire a fake
    * mouse event for each touch event, after a certain time.
    */
-  private _lastTouchEventTime: number;
+  private _lastTouchEventTime!: number;
 
   /** Time at which the last dragging sequence was started. */
-  private _dragStartTime: number;
+  private _dragStartTime!: number;
 
   /** Cached reference to the boundary element. */
   private _boundaryElement: HTMLElement | null = null;
@@ -283,7 +283,7 @@ export class DragRef<T = any> {
   private _direction: Direction = 'ltr';
 
   /** Ref that the current drag item is nested in. */
-  private _parentDragRef: DragRef<unknown> | null;
+  private _parentDragRef: DragRef<unknown> | null = null;
 
   /**
    * Cached shadow root that the element is placed in. `null` means that the element isn't in
@@ -372,7 +372,7 @@ export class DragRef<T = any> {
   }> = this._moveEvents;
 
   /** Arbitrary data that can be attached to the drag item. */
-  data: T;
+  data!: T;
 
   /**
    * Function that can be used to customize the logic of how the position of the drag item
diff --git a/src/cdk/drag-drop/drop-list-ref.ts b/src/cdk/drag-drop/drop-list-ref.ts
index 2e2fd8436676..2c2638981b9a 100644
--- a/src/cdk/drag-drop/drop-list-ref.ts
+++ b/src/cdk/drag-drop/drop-list-ref.ts
@@ -137,10 +137,10 @@ export class DropListRef<T = any> {
   }>();
 
   /** Arbitrary data that can be attached to the drop list. */
-  data: T;
+  data!: T;
 
   /** Element that is the direct parent of the drag items. */
-  private _container: HTMLElement;
+  private _container!: HTMLElement;
 
   /** Whether an item in the list is being dragged. */
   private _isDragging = false;
@@ -149,7 +149,7 @@ export class DropListRef<T = any> {
   private _parentPositions: ParentPositionTracker;
 
   /** Strategy being used to sort items within the list. */
-  private _sortStrategy: DropListSortStrategy;
+  private _sortStrategy!: DropListSortStrategy;
 
   /** Cached `DOMRect` of the drop list. */
   private _domRect: DOMRect | undefined;
@@ -173,7 +173,7 @@ export class DropListRef<T = any> {
   private _horizontalScrollDirection = AutoScrollHorizontalDirection.NONE;
 
   /** Node that is being auto-scrolled. */
-  private _scrollNode: HTMLElement | Window;
+  private _scrollNode!: HTMLElement | Window;
 
   /** Used to signal to the current auto-scroll sequence when to stop. */
   private readonly _stopScrollTimers = new Subject<void>();
@@ -188,7 +188,7 @@ export class DropListRef<T = any> {
   private _scrollableElements: HTMLElement[] = [];
 
   /** Initial value for the element's `scroll-snap-type` style. */
-  private _initialScrollSnap: string;
+  private _initialScrollSnap!: string;
 
   /** Direction of the list's layout. */
   private _direction: Direction = 'ltr';
diff --git a/src/cdk/drag-drop/preview-ref.ts b/src/cdk/drag-drop/preview-ref.ts
index 7ffab115a7fb..f4116ed41cac 100644
--- a/src/cdk/drag-drop/preview-ref.ts
+++ b/src/cdk/drag-drop/preview-ref.ts
@@ -34,10 +34,10 @@ const importantProperties = new Set([
 
 export class PreviewRef {
   /** Reference to the view of the preview element. */
-  private _previewEmbeddedView: EmbeddedViewRef<any> | null;
+  private _previewEmbeddedView: EmbeddedViewRef<any> | null = null;
 
   /** Reference to the preview element. */
-  private _preview: HTMLElement;
+  private _preview!: HTMLElement;
 
   get element(): HTMLElement {
     return this._preview;
diff --git a/src/cdk/drag-drop/sorting/mixed-sort-strategy.ts b/src/cdk/drag-drop/sorting/mixed-sort-strategy.ts
index d863fec910d6..e35e0d8c3206 100644
--- a/src/cdk/drag-drop/sorting/mixed-sort-strategy.ts
+++ b/src/cdk/drag-drop/sorting/mixed-sort-strategy.ts
@@ -19,10 +19,10 @@ import type {DragRef} from '../drag-ref';
  */
 export class MixedSortStrategy implements DropListSortStrategy {
   /** Root element container of the drop list. */
-  private _element: HTMLElement;
+  private _element!: HTMLElement;
 
   /** Function used to determine if an item can be sorted into a specific index. */
-  private _sortPredicate: SortPredicate<DragRef>;
+  private _sortPredicate!: SortPredicate<DragRef>;
 
   /** Lazily-resolved root node containing the list. Use `_getRootNode` to read this. */
   private _rootNode: DocumentOrShadowRoot | undefined;
@@ -32,7 +32,7 @@ export class MixedSortStrategy implements DropListSortStrategy {
    * that were there at the start of the sequence, as well as any items that have been dragged
    * in, but haven't been dropped yet.
    */
-  private _activeItems: DragRef[];
+  private _activeItems!: DragRef[];
 
   /**
    * Keeps track of the item that was last swapped with the dragged item, as well as what direction
diff --git a/src/cdk/drag-drop/sorting/single-axis-sort-strategy.ts b/src/cdk/drag-drop/sorting/single-axis-sort-strategy.ts
index 68c9c39e94d7..648f52cf6b5f 100644
--- a/src/cdk/drag-drop/sorting/single-axis-sort-strategy.ts
+++ b/src/cdk/drag-drop/sorting/single-axis-sort-strategy.ts
@@ -36,10 +36,10 @@ interface CachedItemPosition<T> {
  */
 export class SingleAxisSortStrategy implements DropListSortStrategy {
   /** Root element container of the drop list. */
-  private _element: HTMLElement;
+  private _element!: HTMLElement;
 
   /** Function used to determine if an item can be sorted into a specific index. */
-  private _sortPredicate: SortPredicate<DragRef>;
+  private _sortPredicate!: SortPredicate<DragRef>;
 
   /** Cache of the dimensions of all the items inside the container. */
   private _itemPositions: CachedItemPosition<DragRef>[] = [];
@@ -49,13 +49,13 @@ export class SingleAxisSortStrategy implements DropListSortStrategy {
    * that were there at the start of the sequence, as well as any items that have been dragged
    * in, but haven't been dropped yet.
    */
-  private _activeDraggables: DragRef[];
+  private _activeDraggables!: DragRef[];
 
   /** Direction in which the list is oriented. */
   orientation: 'vertical' | 'horizontal' = 'vertical';
 
   /** Layout direction of the drop list. */
-  direction: Direction;
+  direction: Direction = 'ltr';
 
   constructor(private _dragDropRegistry: DragDropRegistry) {}
 
diff --git a/src/cdk/listbox/listbox.spec.ts b/src/cdk/listbox/listbox.spec.ts
index a64d1ba0a1e6..d588431d4b5b 100644
--- a/src/cdk/listbox/listbox.spec.ts
+++ b/src/cdk/listbox/listbox.spec.ts
@@ -123,7 +123,7 @@ describe('CdkOption and CdkListbox', () => {
         expect(options[i].isSelected()).toBeFalse();
         expect(optionEls[i].getAttribute('aria-selected')).toBe('false');
       }
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should update when selection is changed programmatically', () => {
@@ -134,7 +134,7 @@ describe('CdkOption and CdkListbox', () => {
       expect(listbox.value).toEqual(['orange']);
       expect(options[1].isSelected()).toBeTrue();
       expect(optionEls[1].getAttribute('aria-selected')).toBe('true');
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should update on option clicked', () => {
@@ -403,7 +403,7 @@ describe('CdkOption and CdkListbox', () => {
       fixture.detectChanges();
 
       expect(listbox.value).toEqual([]);
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should not change selection on click in a disabled listbox', () => {
@@ -415,7 +415,7 @@ describe('CdkOption and CdkListbox', () => {
       fixture.detectChanges();
 
       expect(listbox.value).toEqual([]);
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should not change selection on keyboard activation in a disabled listbox', () => {
@@ -430,7 +430,7 @@ describe('CdkOption and CdkListbox', () => {
       fixture.detectChanges();
 
       expect(listbox.value).toEqual([]);
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should not change selection on click of a disabled option', () => {
@@ -446,7 +446,7 @@ describe('CdkOption and CdkListbox', () => {
       fixture.detectChanges();
 
       expect(listbox.value).toEqual([]);
-      expect(fixture.componentInstance.changedOption).toBeUndefined();
+      expect(fixture.componentInstance.changedOption).toBe(null);
     });
 
     it('should not handle type ahead on a disabled listbox', async (...args: unknown[]) => {
@@ -985,7 +985,7 @@ describe('CdkOption and CdkListbox', () => {
   imports: [CdkListbox, CdkOption],
 })
 class ListboxWithOptions {
-  changedOption: CdkOption<string> | null;
+  changedOption: CdkOption<string> | null = null;
   isListboxDisabled = signal(false);
   isAppleDisabled = false;
   isOrangeDisabled = false;
@@ -994,12 +994,12 @@ class ListboxWithOptions {
   navigationWraps = true;
   navigationSkipsDisabled = true;
   appleRendered = true;
-  listboxId: string;
-  listboxTabindex: number;
-  appleId: string;
-  appleTabindex: number;
+  listboxId!: string;
+  listboxTabindex: number | undefined;
+  appleId!: string;
+  appleTabindex: number | undefined;
   orientation: 'horizontal' | 'vertical' = 'vertical';
-  selectedValue: string[];
+  selectedValue: string[] = [];
 
   onSelectionChange(event: ListboxValueChangeEvent<string>) {
     this.changedOption = event.option;
diff --git a/src/cdk/listbox/listbox.ts b/src/cdk/listbox/listbox.ts
index 8a327f9a15c4..106cad5cde25 100644
--- a/src/cdk/listbox/listbox.ts
+++ b/src/cdk/listbox/listbox.ts
@@ -108,17 +108,17 @@ export class CdkOption<T = unknown> implements ListKeyManagerOption, Highlightab
   set id(value) {
     this._id = value;
   }
-  private _id: string;
+  private _id: string | undefined;
   private _generatedId = inject(_IdGenerator).getId('cdk-option-');
 
   /** The value of this option. */
-  @Input('cdkOption') value: T;
+  @Input('cdkOption') value!: T;
 
   /**
    * The text used to locate this item during listbox typeahead. If not specified,
    * the `textContent` of the item will be used.
    */
-  @Input('cdkOptionTypeaheadLabel') typeaheadLabel: string | null;
+  @Input('cdkOptionTypeaheadLabel') typeaheadLabel: string | null = null;
 
   /** Whether this option is disabled. */
   @Input({alias: 'cdkOptionDisabled', transform: booleanAttribute})
@@ -271,7 +271,7 @@ export class CdkListbox<T = unknown> implements AfterContentInit, OnDestroy, Con
   set id(value) {
     this._id = value;
   }
-  private _id: string;
+  private _id: string | undefined;
   private _generatedId = inject(_IdGenerator).getId('cdk-listbox-');
 
   /** The tabindex to use when the listbox is enabled. */
@@ -384,13 +384,13 @@ export class CdkListbox<T = unknown> implements AfterContentInit, OnDestroy, Con
   @Output('cdkListboxValueChange') readonly valueChange = new Subject<ListboxValueChangeEvent<T>>();
 
   /** The child options in this listbox. */
-  @ContentChildren(CdkOption, {descendants: true}) protected options: QueryList<CdkOption<T>>;
+  @ContentChildren(CdkOption, {descendants: true}) protected options!: QueryList<CdkOption<T>>;
 
   /** The selection model used by the listbox. */
   protected selectionModel = new ListboxSelectionModel<T>();
 
   /** The key manager that manages keyboard navigation for this listbox. */
-  protected listKeyManager: ActiveDescendantKeyManager<CdkOption<T>>;
+  protected listKeyManager!: ActiveDescendantKeyManager<CdkOption<T>>;
 
   /** Emits when the listbox is destroyed. */
   protected readonly destroyed = new Subject<void>();
diff --git a/src/cdk/menu/context-menu-trigger.spec.ts b/src/cdk/menu/context-menu-trigger.spec.ts
index 84a8043777af..609bb5a92915 100644
--- a/src/cdk/menu/context-menu-trigger.spec.ts
+++ b/src/cdk/menu/context-menu-trigger.spec.ts
@@ -286,7 +286,7 @@ describe('CdkContextMenuTrigger', () => {
   describe('with menubar and inline menu on page', () => {
     let fixture: ComponentFixture<ContextMenuWithMenuBarAndInlineMenu>;
     let nativeMenuBar: HTMLElement;
-    let nativeMenuBarTrigger: HTMLElement;
+    let nativeMenuBarTrigger!: HTMLElement;
 
     beforeEach(() => {
       fixture = TestBed.createComponent(ContextMenuWithMenuBarAndInlineMenu);
@@ -423,12 +423,12 @@ describe('CdkContextMenuTrigger', () => {
   imports: [CdkContextMenuTrigger, CdkMenu, CdkMenuItem],
 })
 class SimpleContextMenu {
-  @ViewChild(CdkContextMenuTrigger) trigger: CdkContextMenuTrigger;
-  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) triggerElement: ElementRef<HTMLElement>;
+  @ViewChild(CdkContextMenuTrigger) trigger!: CdkContextMenuTrigger;
+  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) triggerElement!: ElementRef<HTMLElement>;
   @ViewChild(CdkMenu) menu?: CdkMenu;
   @ViewChild(CdkMenu, {read: ElementRef}) nativeMenu?: ElementRef<HTMLElement>;
 
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -452,11 +452,11 @@ class SimpleContextMenu {
   imports: [CdkContextMenuTrigger, CdkMenu],
 })
 class NestedContextMenu {
-  @ViewChild('cut_trigger', {read: ElementRef}) cutContext: ElementRef<HTMLElement>;
-  @ViewChild('copy_trigger', {read: ElementRef}) copyContext: ElementRef<HTMLElement>;
+  @ViewChild('cut_trigger', {read: ElementRef}) cutContext!: ElementRef<HTMLElement>;
+  @ViewChild('copy_trigger', {read: ElementRef}) copyContext!: ElementRef<HTMLElement>;
 
-  @ViewChild('cut_menu', {read: CdkMenu}) cutMenu: CdkMenu;
-  @ViewChild('copy_menu', {read: CdkMenu}) copyMenu: CdkMenu;
+  @ViewChild('cut_menu', {read: CdkMenu}) cutMenu!: CdkMenu;
+  @ViewChild('copy_menu', {read: CdkMenu}) copyMenu!: CdkMenu;
 
   copyMenuDisabled = false;
 }
@@ -478,11 +478,11 @@ class NestedContextMenu {
   imports: [CdkContextMenuTrigger, CdkMenuTrigger, CdkMenu, CdkMenuItem],
 })
 class ContextMenuWithSubmenu {
-  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) context: ElementRef<HTMLElement>;
-  @ViewChild(CdkMenuTrigger, {read: ElementRef}) triggerNativeElement: ElementRef<HTMLElement>;
+  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) context!: ElementRef<HTMLElement>;
+  @ViewChild(CdkMenuTrigger, {read: ElementRef}) triggerNativeElement!: ElementRef<HTMLElement>;
 
-  @ViewChild('cut_menu', {read: CdkMenu}) cutMenu: CdkMenu;
-  @ViewChild('copy_menu', {read: CdkMenu}) copyMenu: CdkMenu;
+  @ViewChild('cut_menu', {read: CdkMenu}) cutMenu!: CdkMenu;
+  @ViewChild('copy_menu', {read: CdkMenu}) copyMenu!: CdkMenu;
 }
 
 @Component({
@@ -509,16 +509,16 @@ class ContextMenuWithSubmenu {
   imports: [CdkContextMenuTrigger, CdkMenuTrigger, CdkMenu, CdkMenuItem, CdkMenuBar],
 })
 class ContextMenuWithMenuBarAndInlineMenu {
-  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar: ElementRef;
-  @ViewChild('trigger', {read: ElementRef}) nativeMenuBarTrigger: ElementRef;
+  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar!: ElementRef;
+  @ViewChild('trigger', {read: ElementRef}) nativeMenuBarTrigger!: ElementRef;
 
   @ViewChild('context_menu') contextMenu?: CdkMenu;
-  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) trigger: ElementRef<HTMLElement>;
+  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) trigger!: ElementRef<HTMLElement>;
 
   @ViewChild('file_menu') fileMenu?: CdkMenu;
 
-  @ViewChild('inline_menu') nativeInlineMenu: ElementRef;
-  @ViewChild('inline_menu_button') nativeInlineMenuButton: ElementRef;
+  @ViewChild('inline_menu') nativeInlineMenu!: ElementRef;
+  @ViewChild('inline_menu_button') nativeInlineMenuButton!: ElementRef;
 }
 
 @Component({
@@ -538,9 +538,9 @@ class ContextMenuWithMenuBarAndInlineMenu {
   imports: [CdkMenuBar, CdkContextMenuTrigger, CdkMenu, CdkMenuItem, CdkMenuTrigger],
 })
 class MenuBarAndContextTriggerShareMenu {
-  @ViewChild(CdkMenuTrigger) menuBarTrigger: CdkMenuTrigger;
-  @ViewChild(CdkContextMenuTrigger) contextTrigger: CdkContextMenuTrigger;
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChild(CdkMenuTrigger) menuBarTrigger!: CdkMenuTrigger;
+  @ViewChild(CdkContextMenuTrigger) contextTrigger!: CdkContextMenuTrigger;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -554,6 +554,6 @@ class MenuBarAndContextTriggerShareMenu {
   imports: [CdkContextMenuTrigger, CdkMenu],
 })
 class ContextTriggerWithData {
-  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) triggerElement: ElementRef<HTMLElement>;
+  @ViewChild(CdkContextMenuTrigger, {read: ElementRef}) triggerElement!: ElementRef<HTMLElement>;
   menuData: unknown;
 }
diff --git a/src/cdk/menu/menu-aim.ts b/src/cdk/menu/menu-aim.ts
index 981f33f16759..2610532a247e 100644
--- a/src/cdk/menu/menu-aim.ts
+++ b/src/cdk/menu/menu-aim.ts
@@ -117,13 +117,13 @@ export class TargetMenuAim implements MenuAim, OnDestroy {
   private readonly _points: Point[] = [];
 
   /** Reference to the root menu in which we are tracking mouse moves. */
-  private _menu: Menu;
+  private _menu!: Menu;
 
   /** Reference to the root menu's mouse manager. */
-  private _pointerTracker: PointerFocusTracker<Toggler & FocusableElement>;
+  private _pointerTracker!: PointerFocusTracker<Toggler & FocusableElement>;
 
   /** The id associated with the current timeout call waiting to resolve. */
-  private _timeoutId: number | null;
+  private _timeoutId: number | null = null;
 
   /** Emits when this service is destroyed. */
   private readonly _destroyed: Subject<void> = new Subject();
diff --git a/src/cdk/menu/menu-bar.spec.ts b/src/cdk/menu/menu-bar.spec.ts
index 348fad1c0c5c..a7017fe5b644 100644
--- a/src/cdk/menu/menu-bar.spec.ts
+++ b/src/cdk/menu/menu-bar.spec.ts
@@ -1115,11 +1115,11 @@ class MenuBarRadioGroup {}
 })
 class MultiMenuWithSubmenu {
   clickEmitter = new EventEmitter<void>();
-  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar: ElementRef;
+  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar!: ElementRef;
 
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems: QueryList<ElementRef>;
+  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems!: QueryList<ElementRef>;
 }
 
 @Component({
@@ -1140,13 +1140,13 @@ class MultiMenuWithSubmenu {
   imports: [CdkMenuModule],
 })
 class MenuWithCheckboxes {
-  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar: ElementRef;
+  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar!: ElementRef;
 
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems: QueryList<ElementRef>;
+  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItemCheckbox) checkboxItems: QueryList<CdkMenuItemCheckbox>;
+  @ViewChildren(CdkMenuItemCheckbox) checkboxItems!: QueryList<CdkMenuItemCheckbox>;
 }
 
 @Component({
@@ -1167,13 +1167,13 @@ class MenuWithCheckboxes {
   imports: [CdkMenuModule],
 })
 class MenuWithRadioButtons {
-  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar: ElementRef;
+  @ViewChild(CdkMenuBar, {read: ElementRef}) nativeMenuBar!: ElementRef;
 
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems: QueryList<ElementRef>;
+  @ViewChildren(CdkMenuItem, {read: ElementRef}) nativeItems!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItemRadio) radioItems: QueryList<CdkMenuItemRadio>;
+  @ViewChildren(CdkMenuItemRadio) radioItems!: QueryList<CdkMenuItemRadio>;
 }
 
 @Component({
@@ -1200,9 +1200,9 @@ class MenuWithRadioButtons {
   imports: [CdkMenuModule],
 })
 class MenuBarWithMenusAndInlineMenu {
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
 
-  @ViewChild('inline_menu_item') nativeInlineMenuItem: ElementRef;
+  @ViewChild('inline_menu_item') nativeInlineMenuItem!: ElementRef;
 }
diff --git a/src/cdk/menu/menu-base.ts b/src/cdk/menu/menu-base.ts
index 42fae274aac6..c6f2fbe48c29 100644
--- a/src/cdk/menu/menu-base.ts
+++ b/src/cdk/menu/menu-base.ts
@@ -69,7 +69,7 @@ export abstract class CdkMenuBase
 
   /** All items inside the menu, including ones that belong to other menus. */
   @ContentChildren(CdkMenuItem, {descendants: true})
-  protected _allItems: QueryList<CdkMenuItem>;
+  protected _allItems!: QueryList<CdkMenuItem>;
 
   /** The id of the menu's host element. */
   @Input() id: string = inject(_IdGenerator).getId('cdk-menu-');
@@ -87,7 +87,7 @@ export abstract class CdkMenuBase
   isInline = false;
 
   /** Handles keyboard events for the menu. */
-  protected keyManager: FocusKeyManager<CdkMenuItem>;
+  protected keyManager!: FocusKeyManager<CdkMenuItem>;
 
   /** Emits when the MenuBar is destroyed. */
   protected readonly destroyed: Subject<void> = new Subject();
diff --git a/src/cdk/menu/menu-group.spec.ts b/src/cdk/menu/menu-group.spec.ts
index f23620d3d379..46bfecb48f80 100644
--- a/src/cdk/menu/menu-group.spec.ts
+++ b/src/cdk/menu/menu-group.spec.ts
@@ -98,7 +98,7 @@ describe('MenuGroup', () => {
   imports: [CdkMenuModule],
 })
 class CheckboxMenu {
-  @ViewChild(CdkMenuItem) readonly trigger: CdkMenuItem;
+  @ViewChild(CdkMenuItem) readonly trigger!: CdkMenuItem;
 }
 
 @Component({
diff --git a/src/cdk/menu/menu-item-radio.ts b/src/cdk/menu/menu-item-radio.ts
index 8fbd60907995..4bf985acb30f 100644
--- a/src/cdk/menu/menu-item-radio.ts
+++ b/src/cdk/menu/menu-item-radio.ts
@@ -41,7 +41,9 @@ export class CdkMenuItemRadio extends CdkMenuItemSelectable implements OnDestroy
 
   constructor() {
     super();
-    this._registerDispatcherListener();
+    this._removeDispatcherListener = this._selectionDispatcher.listen((id: string) => {
+      this.checked = this._id === id;
+    });
   }
 
   override ngOnDestroy() {
@@ -62,11 +64,4 @@ export class CdkMenuItemRadio extends CdkMenuItemSelectable implements OnDestroy
       this._selectionDispatcher.notify(this._id, '');
     }
   }
-
-  /** Configure the unique selection dispatcher listener in order to toggle the checked state  */
-  private _registerDispatcherListener() {
-    this._removeDispatcherListener = this._selectionDispatcher.listen((id: string) => {
-      this.checked = this._id === id;
-    });
-  }
 }
diff --git a/src/cdk/menu/menu-item.spec.ts b/src/cdk/menu/menu-item.spec.ts
index 1eade63e3cc3..f2081486dffa 100644
--- a/src/cdk/menu/menu-item.spec.ts
+++ b/src/cdk/menu/menu-item.spec.ts
@@ -164,7 +164,7 @@ class SingleMenuItem {}
   imports: [CdkMenuModule, FakeMatIcon],
 })
 class MenuItemWithIcon {
-  typeahead: string;
+  typeahead: string | null = null;
 }
 
 @Component({
@@ -179,7 +179,7 @@ class MenuItemWithIcon {
   imports: [CdkMenuModule],
 })
 class MenuItemWithIconClass {
-  typeahead: string;
+  typeahead: string | null = null;
 }
 
 @Component({
diff --git a/src/cdk/menu/menu-item.ts b/src/cdk/menu/menu-item.ts
index 45ecaf9822f2..b4be5f390d51 100644
--- a/src/cdk/menu/menu-item.ts
+++ b/src/cdk/menu/menu-item.ts
@@ -76,7 +76,7 @@ export class CdkMenuItem implements FocusableOption, FocusableElement, Toggler,
    * The text used to locate this item during menu typeahead. If not specified,
    * the `textContent` of the item will be used.
    */
-  @Input('cdkMenuitemTypeaheadLabel') typeaheadLabel: string | null;
+  @Input('cdkMenuitemTypeaheadLabel') typeaheadLabel: string | null = null;
 
   /**
    * If this MenuItem is a regular MenuItem, outputs when it is triggered by a keyboard or mouse
diff --git a/src/cdk/menu/menu-stack.spec.ts b/src/cdk/menu/menu-stack.spec.ts
index 4cedd983fc2c..250ee37d250b 100644
--- a/src/cdk/menu/menu-stack.spec.ts
+++ b/src/cdk/menu/menu-stack.spec.ts
@@ -97,8 +97,8 @@ describe('MenuStack', () => {
   imports: [CdkMenuModule],
 })
 class MultiMenuWithSubmenu {
-  @ViewChild(CdkMenuBar) menuBar: CdkMenuBar;
+  @ViewChild(CdkMenuBar) menuBar!: CdkMenuBar;
 
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
diff --git a/src/cdk/menu/menu-trigger-base.ts b/src/cdk/menu/menu-trigger-base.ts
index e5addfc550d6..f9af04696c1f 100644
--- a/src/cdk/menu/menu-trigger-base.ts
+++ b/src/cdk/menu/menu-trigger-base.ts
@@ -88,7 +88,7 @@ export abstract class CdkMenuTriggerBase implements OnDestroy {
    * A list of preferred menu positions to be used when constructing the
    * `FlexibleConnectedPositionStrategy` for this trigger's menu.
    */
-  menuPosition: ConnectedPosition[];
+  menuPosition!: ConnectedPosition[];
 
   /** Emits when the attached menu is requested to open */
   readonly opened: EventEmitter<void> = new EventEmitter();
@@ -97,7 +97,7 @@ export abstract class CdkMenuTriggerBase implements OnDestroy {
   readonly closed: EventEmitter<void> = new EventEmitter();
 
   /** Template reference variable to the menu this trigger opens */
-  menuTemplateRef: TemplateRef<unknown> | null;
+  menuTemplateRef: TemplateRef<unknown> | null = null;
 
   /** Context data to be passed along to the menu template */
   menuData: unknown;
@@ -124,7 +124,7 @@ export abstract class CdkMenuTriggerBase implements OnDestroy {
   protected childMenu?: Menu;
 
   /** The content of the menu panel opened by this trigger. */
-  private _menuPortal: TemplatePortal;
+  private _menuPortal: TemplatePortal | undefined;
 
   /** The injector to use for the child menu opened by this trigger. */
   private _childMenuInjector?: Injector;
diff --git a/src/cdk/menu/menu-trigger.spec.ts b/src/cdk/menu/menu-trigger.spec.ts
index 5ab39eb512c3..a7dfe1649e19 100644
--- a/src/cdk/menu/menu-trigger.spec.ts
+++ b/src/cdk/menu/menu-trigger.spec.ts
@@ -539,8 +539,8 @@ describe('MenuTrigger', () => {
   imports: [CdkMenuBar, CdkMenu, CdkMenuItem, CdkMenuTrigger],
 })
 class TriggerForEmptyMenu {
-  @ViewChild(CdkMenuTrigger) trigger: CdkMenuTrigger;
-  @ViewChild(CdkMenuTrigger, {read: ElementRef}) nativeTrigger: ElementRef;
+  @ViewChild(CdkMenuTrigger) trigger!: CdkMenuTrigger;
+  @ViewChild(CdkMenuTrigger, {read: ElementRef}) nativeTrigger!: ElementRef;
 }
 
 @Component({
@@ -564,13 +564,13 @@ class TriggerForEmptyMenu {
   imports: [CdkMenu, CdkMenuItem, CdkMenuTrigger, CdkMenuBar],
 })
 class MenuBarWithNestedSubMenus {
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
-  @ViewChildren(CdkMenuTrigger, {read: ElementRef}) nativeTriggers: QueryList<ElementRef>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenuTrigger, {read: ElementRef}) nativeTriggers!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenuItem) menuItems: QueryList<CdkMenuItem>;
+  @ViewChildren(CdkMenuItem) menuItems!: QueryList<CdkMenuItem>;
 }
 
 @Component({
@@ -591,11 +591,11 @@ class MenuBarWithNestedSubMenus {
   imports: [CdkMenu, CdkMenuItem, CdkMenuTrigger, CdkMenuBar],
 })
 class TriggersWithSameMenuDifferentMenuBars {
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
-  @ViewChildren(CdkMenuTrigger, {read: ElementRef}) nativeTriggers: QueryList<ElementRef>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenuTrigger, {read: ElementRef}) nativeTriggers!: QueryList<ElementRef>;
 
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
 }
 
 @Component({
@@ -614,8 +614,8 @@ class TriggersWithSameMenuDifferentMenuBars {
   imports: [CdkMenu, CdkMenuItem, CdkMenuTrigger, CdkMenuBar],
 })
 class TriggersWithSameMenuSameMenuBar {
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -633,8 +633,8 @@ class TriggersWithSameMenuSameMenuBar {
   imports: [CdkMenu, CdkMenuItem, CdkMenuTrigger, CdkMenuBar],
 })
 class TriggerOpensItsMenu {
-  @ViewChildren(CdkMenuTrigger) triggers: QueryList<CdkMenuTrigger>;
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenuTrigger) triggers!: QueryList<CdkMenuTrigger>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -658,10 +658,10 @@ class TriggerOpensItsMenu {
   imports: [CdkMenu, CdkMenuItem, CdkMenuTrigger],
 })
 class StandaloneTriggerWithInlineMenu {
-  @ViewChild(CdkMenuItem, {read: ElementRef}) nativeTrigger: ElementRef<HTMLElement>;
-  @ViewChild('submenu_item', {read: ElementRef}) submenuItem?: ElementRef<HTMLElement>;
-  @ViewChild('inline_item', {read: ElementRef}) nativeInlineItem: ElementRef<HTMLElement>;
-  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus: QueryList<ElementRef>;
+  @ViewChild(CdkMenuItem, {read: ElementRef}) nativeTrigger!: ElementRef<HTMLElement>;
+  @ViewChild('submenu_item', {read: ElementRef}) submenuItem!: ElementRef<HTMLElement>;
+  @ViewChild('inline_item', {read: ElementRef}) nativeInlineItem!: ElementRef<HTMLElement>;
+  @ViewChildren(CdkMenu, {read: ElementRef}) nativeMenus!: QueryList<ElementRef>;
   useButtonTrigger = true;
 }
 
@@ -689,8 +689,8 @@ class TriggerWithData {
 })
 class TriggerWithNullValue {
   @ViewChild(CdkMenuTrigger, {static: true})
-  trigger: CdkMenuTrigger;
+  trigger!: CdkMenuTrigger;
 
   @ViewChild(CdkMenuTrigger, {static: true, read: ElementRef})
-  nativeTrigger: ElementRef<HTMLElement>;
+  nativeTrigger!: ElementRef<HTMLElement>;
 }
diff --git a/src/cdk/menu/menu-trigger.ts b/src/cdk/menu/menu-trigger.ts
index 3b4d5b48dee3..9f7c63a642ed 100644
--- a/src/cdk/menu/menu-trigger.ts
+++ b/src/cdk/menu/menu-trigger.ts
@@ -85,7 +85,7 @@ export class CdkMenuTrigger extends CdkMenuTriggerBase implements OnChanges, OnD
   private readonly _directionality = inject(Directionality, {optional: true});
   private readonly _renderer = inject(Renderer2);
   private readonly _injector = inject(Injector);
-  private _cleanupMouseenter: () => void;
+  private _cleanupMouseenter!: () => void;
 
   /** The app's menu tracking registry */
   private readonly _menuTracker = inject(MenuTracker);
diff --git a/src/cdk/menu/menu.spec.ts b/src/cdk/menu/menu.spec.ts
index faf38d7255c3..b41fb1c0beb3 100644
--- a/src/cdk/menu/menu.spec.ts
+++ b/src/cdk/menu/menu.spec.ts
@@ -530,7 +530,7 @@ describe('Menu', () => {
   imports: [CdkMenuModule],
 })
 class MenuCheckboxGroup {
-  @ViewChild(CdkMenuItem) readonly trigger: CdkMenuItem;
+  @ViewChild(CdkMenuItem) readonly trigger!: CdkMenuItem;
 }
 
 @Component({
@@ -596,11 +596,11 @@ class InlineMenu {}
   imports: [CdkMenuModule],
 })
 class WithComplexNestedMenus {
-  @ViewChild('file_trigger', {read: ElementRef}) nativeFileTrigger: ElementRef<HTMLElement>;
-  @ViewChild('edit_trigger', {read: ElementRef}) nativeEditTrigger?: ElementRef<HTMLElement>;
-  @ViewChild('share_trigger', {read: ElementRef}) nativeShareTrigger?: ElementRef<HTMLElement>;
+  @ViewChild('file_trigger', {read: ElementRef}) nativeFileTrigger!: ElementRef<HTMLElement>;
+  @ViewChild('edit_trigger', {read: ElementRef}) nativeEditTrigger!: ElementRef<HTMLElement>;
+  @ViewChild('share_trigger', {read: ElementRef}) nativeShareTrigger!: ElementRef<HTMLElement>;
 
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -656,11 +656,11 @@ class WithComplexNestedMenus {
   imports: [CdkMenuModule],
 })
 class WithComplexNestedMenusOnBottom {
-  @ViewChild('file_trigger', {read: ElementRef}) nativeFileTrigger: ElementRef<HTMLElement>;
-  @ViewChild('edit_trigger', {read: ElementRef}) nativeEditTrigger?: ElementRef<HTMLElement>;
-  @ViewChild('share_trigger', {read: ElementRef}) nativeShareTrigger?: ElementRef<HTMLElement>;
+  @ViewChild('file_trigger', {read: ElementRef}) nativeFileTrigger!: ElementRef<HTMLElement>;
+  @ViewChild('edit_trigger', {read: ElementRef}) nativeEditTrigger!: ElementRef<HTMLElement>;
+  @ViewChild('share_trigger', {read: ElementRef}) nativeShareTrigger!: ElementRef<HTMLElement>;
 
-  @ViewChildren(CdkMenu) menus: QueryList<CdkMenu>;
+  @ViewChildren(CdkMenu) menus!: QueryList<CdkMenu>;
 }
 
 @Component({
@@ -675,7 +675,7 @@ class WithComplexNestedMenusOnBottom {
   imports: [CdkMenuModule],
 })
 class MenuWithActiveItem {
-  @ViewChild(CdkMenu) menu: CdkMenu;
+  @ViewChild(CdkMenu) menu!: CdkMenu;
 }
 
 @Component({
@@ -694,6 +694,6 @@ class MenuWithActiveItem {
   imports: [CdkMenuModule],
 })
 class NestedMenuDefinition {
-  @ViewChild('root', {read: CdkMenu}) root: CdkMenu;
-  @ViewChild('inner', {read: CdkMenu}) inner: CdkMenu;
+  @ViewChild('root', {read: CdkMenu}) root!: CdkMenu;
+  @ViewChild('inner', {read: CdkMenu}) inner!: CdkMenu;
 }
diff --git a/src/cdk/menu/pointer-focus-tracker.spec.ts b/src/cdk/menu/pointer-focus-tracker.spec.ts
index 6fba4431e432..6f0e35ce3222 100644
--- a/src/cdk/menu/pointer-focus-tracker.spec.ts
+++ b/src/cdk/menu/pointer-focus-tracker.spec.ts
@@ -125,10 +125,10 @@ class MultiElementWithConditionalComponent implements AfterViewInit {
   showThird = false;
 
   /** All mock elements. */
-  @ViewChildren(MockWrapper) readonly _allItems: QueryList<MockWrapper>;
+  @ViewChildren(MockWrapper) readonly _allItems!: QueryList<MockWrapper>;
 
   /** Manages elements under mouse focus. */
-  focusTracker: PointerFocusTracker<MockWrapper>;
+  focusTracker!: PointerFocusTracker<MockWrapper>;
 
   ngAfterViewInit() {
     this.focusTracker = new PointerFocusTracker(this._renderer, this._allItems);
diff --git a/src/cdk/observers/observe-content.spec.ts b/src/cdk/observers/observe-content.spec.ts
index 6cd36f13bf1e..a23c72588cec 100644
--- a/src/cdk/observers/observe-content.spec.ts
+++ b/src/cdk/observers/observe-content.spec.ts
@@ -283,6 +283,6 @@ class ComponentWithDebouncedListener {
   imports: [ObserversModule],
 })
 class UnobservedComponentWithTextContent {
-  @ViewChild('contentEl') contentEl: ElementRef;
+  @ViewChild('contentEl') contentEl!: ElementRef<HTMLElement>;
   text = '';
 }
diff --git a/src/cdk/observers/observe-content.ts b/src/cdk/observers/observe-content.ts
index b6eab4a88634..3fa0664a7aac 100644
--- a/src/cdk/observers/observe-content.ts
+++ b/src/cdk/observers/observe-content.ts
@@ -203,13 +203,13 @@ export class CdkObserveContent implements AfterContentInit, OnDestroy {
   /** Debounce interval for emitting the changes. */
   @Input()
   get debounce(): number {
-    return this._debounce;
+    return this._debounce!;
   }
   set debounce(value: NumberInput) {
     this._debounce = coerceNumberProperty(value);
     this._subscribe();
   }
-  private _debounce: number;
+  private _debounce: number | undefined;
 
   private _currentSubscription: Subscription | null = null;
 
diff --git a/src/cdk/observers/private/shared-resize-observer.spec.ts b/src/cdk/observers/private/shared-resize-observer.spec.ts
index 15e38cbdb79b..3354a03bda61 100644
--- a/src/cdk/observers/private/shared-resize-observer.spec.ts
+++ b/src/cdk/observers/private/shared-resize-observer.spec.ts
@@ -137,7 +137,7 @@ describe('SharedResizeObserver', () => {
   `,
 })
 export class TestComponent {
-  @ViewChild('el1') el1: ElementRef<Element>;
-  @ViewChild('el2') el2: ElementRef<Element>;
+  @ViewChild('el1') el1!: ElementRef<Element>;
+  @ViewChild('el2') el2!: ElementRef<Element>;
   resizeObserver = inject(SharedResizeObserver);
 }
diff --git a/src/cdk/overlay/dispatchers/base-overlay-dispatcher.ts b/src/cdk/overlay/dispatchers/base-overlay-dispatcher.ts
index b4de56aeb0d7..9c4c28490271 100644
--- a/src/cdk/overlay/dispatchers/base-overlay-dispatcher.ts
+++ b/src/cdk/overlay/dispatchers/base-overlay-dispatcher.ts
@@ -20,7 +20,7 @@ export abstract class BaseOverlayDispatcher implements OnDestroy {
   _attachedOverlays: OverlayRef[] = [];
 
   protected _document = inject(DOCUMENT);
-  protected _isAttached: boolean;
+  protected _isAttached = false;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/overlay/dispatchers/overlay-outside-click-dispatcher.ts b/src/cdk/overlay/dispatchers/overlay-outside-click-dispatcher.ts
index b66e0259d1ae..5077f69cfe0d 100644
--- a/src/cdk/overlay/dispatchers/overlay-outside-click-dispatcher.ts
+++ b/src/cdk/overlay/dispatchers/overlay-outside-click-dispatcher.ts
@@ -22,9 +22,9 @@ export class OverlayOutsideClickDispatcher extends BaseOverlayDispatcher {
   private _ngZone = inject(NgZone);
   private _renderer = inject(RendererFactory2).createRenderer(null, null);
 
-  private _cursorOriginalValue: string;
+  private _cursorOriginalValue!: string;
   private _cursorStyleIsSet = false;
-  private _pointerDownEventTarget: HTMLElement | null;
+  private _pointerDownEventTarget: HTMLElement | null = null;
   private _cleanups: (() => void)[] | undefined;
 
   /** Add a new overlay to the list of attached overlay refs. */
diff --git a/src/cdk/overlay/overlay-container.ts b/src/cdk/overlay/overlay-container.ts
index 2d22868b0d3a..5b2f8a69f86c 100644
--- a/src/cdk/overlay/overlay-container.ts
+++ b/src/cdk/overlay/overlay-container.ts
@@ -32,7 +32,7 @@ export class _CdkOverlayStyleLoader {}
 export class OverlayContainer implements OnDestroy {
   protected _platform = inject(Platform);
 
-  protected _containerElement: HTMLElement;
+  protected _containerElement: HTMLElement | undefined;
   protected _document = inject(DOCUMENT);
   protected _styleLoader = inject(_CdkPrivateStyleLoader);
 
@@ -56,7 +56,7 @@ export class OverlayContainer implements OnDestroy {
       this._createContainer();
     }
 
-    return this._containerElement;
+    return this._containerElement!;
   }
 
   /**
diff --git a/src/cdk/overlay/overlay-directives.ts b/src/cdk/overlay/overlay-directives.ts
index f69d079035a9..77d671fba1b7 100644
--- a/src/cdk/overlay/overlay-directives.ts
+++ b/src/cdk/overlay/overlay-directives.ts
@@ -150,29 +150,30 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
   private _attachSubscription = Subscription.EMPTY;
   private _detachSubscription = Subscription.EMPTY;
   private _positionSubscription = Subscription.EMPTY;
-  private _offsetX: number;
-  private _offsetY: number;
-  private _position: FlexibleConnectedPositionStrategy;
+  private _offsetX: number | undefined;
+  private _offsetY: number | undefined;
+  private _position: FlexibleConnectedPositionStrategy | undefined;
   private _scrollStrategyFactory = inject(CDK_CONNECTED_OVERLAY_SCROLL_STRATEGY);
   private _ngZone = inject(NgZone);
 
   /** Origin for the connected overlay. */
   @Input('cdkConnectedOverlayOrigin')
-  origin: CdkOverlayOrigin | FlexibleConnectedPositionStrategyOrigin;
+  origin!: CdkOverlayOrigin | FlexibleConnectedPositionStrategyOrigin;
 
   /** Registered connected position pairs. */
-  @Input('cdkConnectedOverlayPositions') positions: ConnectedPosition[];
+  @Input('cdkConnectedOverlayPositions') positions!: ConnectedPosition[];
 
   /**
    * This input overrides the positions input if specified. It lets users pass
    * in arbitrary positioning strategies.
    */
-  @Input('cdkConnectedOverlayPositionStrategy') positionStrategy: FlexibleConnectedPositionStrategy;
+  @Input('cdkConnectedOverlayPositionStrategy')
+  positionStrategy!: FlexibleConnectedPositionStrategy;
 
   /** The offset in pixels for the overlay connection point on the x-axis */
   @Input('cdkConnectedOverlayOffsetX')
   get offsetX(): number {
-    return this._offsetX;
+    return this._offsetX!;
   }
   set offsetX(offsetX: number) {
     this._offsetX = offsetX;
@@ -185,7 +186,7 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
   /** The offset in pixels for the overlay connection point on the y-axis */
   @Input('cdkConnectedOverlayOffsetY')
   get offsetY() {
-    return this._offsetY;
+    return this._offsetY!;
   }
   set offsetY(offsetY: number) {
     this._offsetY = offsetY;
@@ -196,22 +197,22 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
   }
 
   /** The width of the overlay panel. */
-  @Input('cdkConnectedOverlayWidth') width: number | string;
+  @Input('cdkConnectedOverlayWidth') width!: number | string;
 
   /** The height of the overlay panel. */
-  @Input('cdkConnectedOverlayHeight') height: number | string;
+  @Input('cdkConnectedOverlayHeight') height!: number | string;
 
   /** The min width of the overlay panel. */
-  @Input('cdkConnectedOverlayMinWidth') minWidth: number | string;
+  @Input('cdkConnectedOverlayMinWidth') minWidth!: number | string;
 
   /** The min height of the overlay panel. */
-  @Input('cdkConnectedOverlayMinHeight') minHeight: number | string;
+  @Input('cdkConnectedOverlayMinHeight') minHeight!: number | string;
 
   /** The custom class to be set on the backdrop element. */
-  @Input('cdkConnectedOverlayBackdropClass') backdropClass: string | string[];
+  @Input('cdkConnectedOverlayBackdropClass') backdropClass!: string | string[];
 
   /** The custom class to add to the overlay pane element. */
-  @Input('cdkConnectedOverlayPanelClass') panelClass: string | string[];
+  @Input('cdkConnectedOverlayPanelClass') panelClass!: string | string[];
 
   /** Margin between the overlay and the viewport edges. */
   @Input('cdkConnectedOverlayViewportMargin') viewportMargin: ViewportMargin = 0;
@@ -226,7 +227,7 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
   @Input('cdkConnectedOverlayDisableClose') disableClose: boolean = false;
 
   /** CSS selector which to set the transform origin. */
-  @Input('cdkConnectedOverlayTransformOriginOn') transformOriginSelector: string;
+  @Input('cdkConnectedOverlayTransformOriginOn') transformOriginSelector!: string;
 
   /** Whether or not the overlay should attach a backdrop. */
   @Input({alias: 'cdkConnectedOverlayHasBackdrop', transform: booleanAttribute})
@@ -499,15 +500,15 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
     // Only subscribe to `positionChanges` if requested, because putting
     // together all the information for it can be expensive.
     if (this.positionChange.observers.length > 0) {
-      this._positionSubscription = this._position.positionChanges
-        .pipe(takeWhile(() => this.positionChange.observers.length > 0))
-        .subscribe(position => {
-          this._ngZone.run(() => this.positionChange.emit(position));
-
-          if (this.positionChange.observers.length === 0) {
-            this._positionSubscription.unsubscribe();
-          }
-        });
+      this._positionSubscription = this._position!.positionChanges.pipe(
+        takeWhile(() => this.positionChange.observers.length > 0),
+      ).subscribe(position => {
+        this._ngZone.run(() => this.positionChange.emit(position));
+
+        if (this.positionChange.observers.length === 0) {
+          this._positionSubscription.unsubscribe();
+        }
+      });
     }
 
     this.open = true;
diff --git a/src/cdk/overlay/overlay-ref.ts b/src/cdk/overlay/overlay-ref.ts
index ab9bae62f63c..f60a8a72ad3c 100644
--- a/src/cdk/overlay/overlay-ref.ts
+++ b/src/cdk/overlay/overlay-ref.ts
@@ -51,13 +51,13 @@ export class OverlayRef implements PortalOutlet {
   private _backdropRef: BackdropRef | null = null;
   private _detachContentMutationObserver: MutationObserver | undefined;
   private _detachContentAfterRenderRef: AfterRenderRef | undefined;
-  private _disposed: boolean;
+  private _disposed = false;
 
   /**
    * Reference to the parent of the `_host` at the time it was detached. Used to restore
    * the `_host` to its original position in the DOM when it gets re-attached.
    */
-  private _previousHostParent: HTMLElement;
+  private _previousHostParent!: HTMLElement;
 
   /** Stream of keydown events dispatched to this overlay. */
   readonly _keydownEvents = new Subject<KeyboardEvent>();
diff --git a/src/cdk/overlay/position/connected-position.ts b/src/cdk/overlay/position/connected-position.ts
index 8291436b8490..323f8c51f703 100644
--- a/src/cdk/overlay/position/connected-position.ts
+++ b/src/cdk/overlay/position/connected-position.ts
@@ -81,10 +81,10 @@ export class ConnectionPositionPair {
  *  @docs-private
  */
 export class ScrollingVisibility {
-  isOriginClipped: boolean;
-  isOriginOutsideView: boolean;
-  isOverlayClipped: boolean;
-  isOverlayOutsideView: boolean;
+  isOriginClipped: boolean = false;
+  isOriginOutsideView: boolean = false;
+  isOverlayClipped: boolean = false;
+  isOverlayOutsideView: boolean = false;
 }
 
 /** The change event emitted by the strategy when a fallback position is used. */
diff --git a/src/cdk/overlay/position/flexible-connected-position-strategy.ts b/src/cdk/overlay/position/flexible-connected-position-strategy.ts
index b31c87411b08..c3f2ee0e6201 100644
--- a/src/cdk/overlay/position/flexible-connected-position-strategy.ts
+++ b/src/cdk/overlay/position/flexible-connected-position-strategy.ts
@@ -78,10 +78,10 @@ export type FlexibleOverlayPopoverLocation =
  */
 export class FlexibleConnectedPositionStrategy implements PositionStrategy {
   /** The overlay to which this strategy is attached. */
-  private _overlayRef: OverlayRef;
+  private _overlayRef!: OverlayRef;
 
   /** Whether we're performing the very first positioning of the overlay. */
-  private _isInitialRender: boolean;
+  private _isInitialRender = false;
 
   /** Last size used for the bounding box. Used to avoid resizing the overlay after open. */
   private _lastBoundingBoxSize = {width: 0, height: 0};
@@ -102,16 +102,16 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
   private _positionLocked = false;
 
   /** Cached origin dimensions */
-  private _originRect: Dimensions;
+  private _originRect!: Dimensions;
 
   /** Cached overlay dimensions */
-  private _overlayRect: Dimensions;
+  private _overlayRect!: Dimensions;
 
   /** Cached viewport dimensions */
-  private _viewportRect: Dimensions;
+  private _viewportRect!: Dimensions;
 
   /** Cached container dimensions */
-  private _containerRect: Dimensions;
+  private _containerRect!: Dimensions;
 
   /** Amount of space that must be maintained between the overlay and the right edge of the viewport. */
   private _viewportMargin: ViewportMargin = 0;
@@ -123,25 +123,25 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
   _preferredPositions: ConnectionPositionPair[] = [];
 
   /** The origin element against which the overlay will be positioned. */
-  _origin: FlexibleConnectedPositionStrategyOrigin;
+  _origin!: FlexibleConnectedPositionStrategyOrigin;
 
   /** The overlay pane element. */
-  private _pane: HTMLElement;
+  private _pane!: HTMLElement;
 
   /** Whether the strategy has been disposed of already. */
-  private _isDisposed: boolean;
+  private _isDisposed = false;
 
   /**
    * Parent element for the overlay panel used to constrain the overlay panel's size to fit
    * within the viewport.
    */
-  private _boundingBox: HTMLElement | null;
+  private _boundingBox: HTMLElement | null = null;
 
   /** The last position to have been calculated as the best fit position. */
-  private _lastPosition: ConnectedPosition | null;
+  private _lastPosition: ConnectedPosition | null = null;
 
   /** The last calculated scroll visibility. Only tracked  */
-  private _lastScrollVisibility: ScrollingVisibility | null;
+  private _lastScrollVisibility: ScrollingVisibility | null = null;
 
   /** Subject that emits whenever the position changes. */
   private readonly _positionChanges = new Subject<ConnectedOverlayPositionChange>();
@@ -156,13 +156,13 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
   private _offsetY = 0;
 
   /** Selector to be used when finding the elements on which to set the transform origin. */
-  private _transformOriginSelector: string;
+  private _transformOriginSelector!: string;
 
   /** Keeps track of the CSS classes that the position strategy has applied on the overlay panel. */
   private _appliedPanelClasses: string[] = [];
 
   /** Amount by which the overlay was pushed in each axis during the last time it was positioned. */
-  private _previousPushAmount: {x: number; y: number} | null;
+  private _previousPushAmount: {x: number; y: number} | null = null;
 
   /** Configures where in the DOM to insert the overlay when popovers are enabled. */
   private _popoverLocation: FlexibleOverlayPopoverLocation = 'global';
diff --git a/src/cdk/overlay/position/global-position-strategy.ts b/src/cdk/overlay/position/global-position-strategy.ts
index 2c0f11dabcc4..82142aebc8ae 100644
--- a/src/cdk/overlay/position/global-position-strategy.ts
+++ b/src/cdk/overlay/position/global-position-strategy.ts
@@ -29,7 +29,7 @@ export function createGlobalPositionStrategy(_injector: Injector): GlobalPositio
  */
 export class GlobalPositionStrategy implements PositionStrategy {
   /** The overlay to which this strategy is attached. */
-  private _overlayRef: OverlayRef;
+  private _overlayRef!: OverlayRef;
   private _cssPosition = 'static';
   private _topOffset = '';
   private _bottomOffset = '';
diff --git a/src/cdk/overlay/scroll/block-scroll-strategy.ts b/src/cdk/overlay/scroll/block-scroll-strategy.ts
index e3d28d3e5406..e3a5930e6d59 100644
--- a/src/cdk/overlay/scroll/block-scroll-strategy.ts
+++ b/src/cdk/overlay/scroll/block-scroll-strategy.ts
@@ -28,7 +28,7 @@ export function createBlockScrollStrategy(injector: Injector): BlockScrollStrate
  */
 export class BlockScrollStrategy implements ScrollStrategy {
   private _previousHTMLStyles = {top: '', left: ''};
-  private _previousScrollPosition: {top: number; left: number};
+  private _previousScrollPosition: {top: number; left: number} | undefined;
   private _isEnabled = false;
   private _document: Document;
 
@@ -87,7 +87,7 @@ export class BlockScrollStrategy implements ScrollStrategy {
         htmlStyle.scrollBehavior = bodyStyle.scrollBehavior = 'auto';
       }
 
-      window.scroll(this._previousScrollPosition.left, this._previousScrollPosition.top);
+      window.scroll(this._previousScrollPosition!.left, this._previousScrollPosition!.top);
 
       if (scrollBehaviorSupported) {
         htmlStyle.scrollBehavior = previousHtmlScrollBehavior;
diff --git a/src/cdk/overlay/scroll/close-scroll-strategy.ts b/src/cdk/overlay/scroll/close-scroll-strategy.ts
index 2703e386352d..8c0a3e04e22c 100644
--- a/src/cdk/overlay/scroll/close-scroll-strategy.ts
+++ b/src/cdk/overlay/scroll/close-scroll-strategy.ts
@@ -42,8 +42,8 @@ export function createCloseScrollStrategy(
  */
 export class CloseScrollStrategy implements ScrollStrategy {
   private _scrollSubscription: Subscription | null = null;
-  private _overlayRef: OverlayRef;
-  private _initialScrollPosition: number;
+  private _overlayRef!: OverlayRef;
+  private _initialScrollPosition!: number;
 
   constructor(
     private _scrollDispatcher: ScrollDispatcher,
diff --git a/src/cdk/overlay/scroll/reposition-scroll-strategy.ts b/src/cdk/overlay/scroll/reposition-scroll-strategy.ts
index 1c30c1c6e8b9..a16893ae4b4b 100644
--- a/src/cdk/overlay/scroll/reposition-scroll-strategy.ts
+++ b/src/cdk/overlay/scroll/reposition-scroll-strategy.ts
@@ -46,7 +46,7 @@ export function createRepositionScrollStrategy(
  */
 export class RepositionScrollStrategy implements ScrollStrategy {
   private _scrollSubscription: Subscription | null = null;
-  private _overlayRef: OverlayRef;
+  private _overlayRef!: OverlayRef;
 
   constructor(
     private _scrollDispatcher: ScrollDispatcher,
diff --git a/src/cdk/portal/portal-directives.ts b/src/cdk/portal/portal-directives.ts
index e50814e91e9b..22269dd2111c 100644
--- a/src/cdk/portal/portal-directives.ts
+++ b/src/cdk/portal/portal-directives.ts
@@ -69,7 +69,7 @@ export class CdkPortalOutlet extends BasePortalOutlet implements OnInit, OnDestr
   private _isInitialized = false;
 
   /** Reference to the currently-attached component/view ref. */
-  private _attachedRef: CdkPortalOutletAttachedRef;
+  private _attachedRef: CdkPortalOutletAttachedRef = null;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/portal/portal.ts b/src/cdk/portal/portal.ts
index 7865c6d0781e..e67cf3db866a 100644
--- a/src/cdk/portal/portal.ts
+++ b/src/cdk/portal/portal.ts
@@ -33,7 +33,7 @@ export interface ComponentType<T> {
  * It can be attach to / detached from a `PortalOutlet`.
  */
 export abstract class Portal<T> {
-  private _attachedHost: PortalOutlet | null;
+  private _attachedHost: PortalOutlet | null = null;
 
   /** Attach this portal to a host. */
   attach(host: PortalOutlet): T {
@@ -186,10 +186,10 @@ export interface PortalOutlet {
  */
 export abstract class BasePortalOutlet implements PortalOutlet {
   /** The portal currently attached to the host. */
-  protected _attachedPortal: Portal<any> | null;
+  protected _attachedPortal: Portal<any> | null = null;
 
   /** A function that will permanently dispose this host. */
-  private _disposeFn: (() => void) | null;
+  private _disposeFn: (() => void) | null = null;
 
   /** Whether this host has already been permanently disposed. */
   private _isDisposed: boolean = false;
diff --git a/src/cdk/scrolling/viewport-ruler.ts b/src/cdk/scrolling/viewport-ruler.ts
index 66ea77dd9f79..b3b65a586b36 100644
--- a/src/cdk/scrolling/viewport-ruler.ts
+++ b/src/cdk/scrolling/viewport-ruler.ts
@@ -30,7 +30,7 @@ export class ViewportRuler implements OnDestroy {
   private _listeners: (() => void)[] | undefined;
 
   /** Cached viewport dimensions. */
-  private _viewportSize: {width: number; height: number} | null;
+  private _viewportSize: {width: number; height: number} | null = null;
 
   /** Stream of viewport change events. */
   private readonly _change = new Subject<Event>();
diff --git a/src/cdk/scrolling/virtual-for-of.ts b/src/cdk/scrolling/virtual-for-of.ts
index 564486c70b1a..2173510ea50b 100644
--- a/src/cdk/scrolling/virtual-for-of.ts
+++ b/src/cdk/scrolling/virtual-for-of.ts
@@ -169,13 +169,13 @@ export class CdkVirtualForOf<T>
   private _differ: IterableDiffer<T> | null = null;
 
   /** The most recent data emitted from the DataSource. */
-  private _data: readonly T[];
+  private _data: readonly T[] = [];
 
   /** The currently rendered items. */
-  private _renderedItems: T[];
+  private _renderedItems: T[] = [];
 
   /** The currently rendered range of indices. */
-  private _renderedRange: ListRange;
+  private _renderedRange: ListRange = {start: 0, end: 0};
 
   /** Whether the rendered data should be updated during the next ngDoCheck cycle. */
   private _needsUpdate = false;
diff --git a/src/cdk/scrolling/virtual-scroll-viewport.ts b/src/cdk/scrolling/virtual-scroll-viewport.ts
index e3aeebeb8bd2..27f8ae2ea710 100644
--- a/src/cdk/scrolling/virtual-scroll-viewport.ts
+++ b/src/cdk/scrolling/virtual-scroll-viewport.ts
@@ -137,7 +137,7 @@ export class CdkVirtualScrollViewport extends CdkVirtualScrollable implements On
   );
 
   /** The element that wraps the rendered content. */
-  @ViewChild('contentWrapper', {static: true}) _contentWrapper: ElementRef<HTMLElement>;
+  @ViewChild('contentWrapper', {static: true}) _contentWrapper!: ElementRef<HTMLElement>;
 
   /** A stream that emits whenever the rendered range changes. */
   readonly renderedRangeStream: Observable<ListRange> = this._renderedRangeSubject;
@@ -165,7 +165,7 @@ export class CdkVirtualScrollViewport extends CdkVirtualScrollable implements On
    * The CSS transform applied to the rendered subset of items so that they appear within the bounds
    * of the visible viewport.
    */
-  private _renderedContentTransform: string;
+  private _renderedContentTransform: string | undefined;
 
   /** The currently rendered range of indices. */
   private _renderedRange: ListRange = {start: 0, end: 0};
@@ -177,7 +177,7 @@ export class CdkVirtualScrollViewport extends CdkVirtualScrollable implements On
   private _viewportSize = 0;
 
   /** the currently attached CdkVirtualScrollRepeater. */
-  private _forOf: CdkVirtualScrollRepeater<any> | null;
+  private _forOf: CdkVirtualScrollRepeater<any> | null = null;
 
   /** The last rendered content offset that was set. */
   private _renderedContentOffset = 0;
@@ -545,7 +545,7 @@ export class CdkVirtualScrollViewport extends CdkVirtualScrollable implements On
       // bypassSecurityTrustStyle is banned in Google. However the value is safe, it's composed of
       // string literals, a variable that can only be 'X' or 'Y', and user input that is run through
       // the `Number` function first to coerce it to a numeric value.
-      this._contentWrapper.nativeElement.style.transform = this._renderedContentTransform;
+      this._contentWrapper.nativeElement.style.transform = this._renderedContentTransform!;
       this._renderedContentOffsetSubject.next(this.getOffsetToRenderedContentStart());
 
       afterNextRender(
diff --git a/src/cdk/stepper/stepper.ts b/src/cdk/stepper/stepper.ts
index 06d82f8af560..259a897c1dba 100644
--- a/src/cdk/stepper/stepper.ts
+++ b/src/cdk/stepper/stepper.ts
@@ -60,16 +60,16 @@ export type StepperOrientation = 'horizontal' | 'vertical';
 /** Change event emitted on selection changes. */
 export class StepperSelectionEvent {
   /** Index of the step now selected. */
-  selectedIndex: number;
+  selectedIndex!: number;
 
   /** Index of the step previously selected. */
-  previouslySelectedIndex: number;
+  previouslySelectedIndex!: number;
 
   /** The step instance now selected. */
-  selectedStep: CdkStep;
+  selectedStep!: CdkStep;
 
   /** The step instance previously selected. */
-  previouslySelectedStep: CdkStep;
+  previouslySelectedStep!: CdkStep;
 }
 
 /** The state of each step. */
@@ -115,7 +115,7 @@ export class CdkStep implements OnChanges {
   _displayDefaultIndicatorType: boolean;
 
   /** Template for step label if it exists. */
-  @ContentChild(CdkStepLabel) stepLabel: CdkStepLabel;
+  @ContentChild(CdkStepLabel) stepLabel!: CdkStepLabel;
 
   /** Forms that have been projected into the step. */
   @ContentChildren(
@@ -131,10 +131,10 @@ export class CdkStep implements OnChanges {
   protected _childForms: QueryList<Partial<NgForm | FormGroupDirective>> | undefined;
 
   /** Template for step content. */
-  @ViewChild(TemplateRef, {static: true}) content: TemplateRef<any>;
+  @ViewChild(TemplateRef, {static: true}) content!: TemplateRef<any>;
 
   /** The top level abstract control of the step. */
-  @Input() stepControl: AbstractControl;
+  @Input() stepControl!: AbstractControl;
 
   /** Whether user has attempted to move away from the step. */
   get interacted(): boolean {
@@ -150,19 +150,19 @@ export class CdkStep implements OnChanges {
   readonly interactedStream: EventEmitter<CdkStep> = new EventEmitter<CdkStep>();
 
   /** Plain text label of the step. */
-  @Input() label: string;
+  @Input() label!: string;
 
   /** Error message to display when there's an error. */
-  @Input() errorMessage: string;
+  @Input() errorMessage!: string;
 
   /** Aria label for the tab. */
-  @Input('aria-label') ariaLabel: string;
+  @Input('aria-label') ariaLabel!: string;
 
   /**
    * Reference to the element that the tab is labelled by.
    * Will be cleared if `aria-label` is set at the same time.
    */
-  @Input('aria-labelledby') ariaLabelledby: string;
+  @Input('aria-labelledby') ariaLabelledby!: string;
 
   /** State of the step. */
   @Input()
@@ -329,13 +329,13 @@ export class CdkStepper implements AfterContentInit, AfterViewInit, OnDestroy {
   private _keyManager: FocusKeyManager<FocusableOption> | undefined;
 
   /** Full list of steps inside the stepper, including inside nested steppers. */
-  @ContentChildren(CdkStep, {descendants: true}) _steps: QueryList<CdkStep>;
+  @ContentChildren(CdkStep, {descendants: true}) _steps!: QueryList<CdkStep>;
 
   /** Steps that belong to the current stepper, excluding ones from nested steppers. */
   readonly steps: QueryList<CdkStep> = new QueryList<CdkStep>();
 
   /** The list of step headers of the steps in the stepper. */
-  @ContentChildren(CdkStepHeader, {descendants: true}) _stepHeader: QueryList<CdkStepHeader>;
+  @ContentChildren(CdkStepHeader, {descendants: true}) _stepHeader!: QueryList<CdkStepHeader>;
 
   /** List of step headers sorted based on their DOM order. */
   private _sortedHeaders = new QueryList<CdkStepHeader>();
diff --git a/src/cdk/table/cell.ts b/src/cdk/table/cell.ts
index 3174953b886a..37d4fca1d426 100644
--- a/src/cdk/table/cell.ts
+++ b/src/cdk/table/cell.ts
@@ -89,7 +89,7 @@ export class CdkColumnDef implements CanStick {
   set name(name: string) {
     this._setNameInput(name);
   }
-  protected _name: string;
+  protected _name!: string;
 
   /** Whether the cell is sticky. */
   @Input({transform: booleanAttribute})
@@ -122,26 +122,26 @@ export class CdkColumnDef implements CanStick {
   _stickyEnd: boolean = false;
 
   /** @docs-private */
-  @ContentChild(CdkCellDef) cell: CdkCellDef;
+  @ContentChild(CdkCellDef) cell!: CdkCellDef;
 
   /** @docs-private */
-  @ContentChild(CdkHeaderCellDef) headerCell: CdkHeaderCellDef;
+  @ContentChild(CdkHeaderCellDef) headerCell!: CdkHeaderCellDef;
 
   /** @docs-private */
-  @ContentChild(CdkFooterCellDef) footerCell: CdkFooterCellDef;
+  @ContentChild(CdkFooterCellDef) footerCell!: CdkFooterCellDef;
 
   /**
    * Transformed version of the column name that can be used as part of a CSS classname. Excludes
    * all non-alphanumeric characters and the special characters '-' and '_'. Any characters that
    * do not match are replaced by the '-' character.
    */
-  cssClassFriendlyName: string;
+  cssClassFriendlyName!: string;
 
   /**
    * Class name for cells in this column.
    * @docs-private
    */
-  _columnCssClassName: string[];
+  _columnCssClassName!: string[];
 
   constructor(...args: unknown[]);
   constructor() {}
diff --git a/src/cdk/table/row.ts b/src/cdk/table/row.ts
index 588c83eaf525..1205a883aa30 100644
--- a/src/cdk/table/row.ts
+++ b/src/cdk/table/row.ts
@@ -43,10 +43,10 @@ export abstract class BaseRowDef implements OnChanges {
   protected _differs = inject(IterableDiffers);
 
   /** The columns to be displayed on this row. */
-  columns: Iterable<string>;
+  columns!: Iterable<string>;
 
   /** Differ used to check if any changes were made to the columns. */
-  protected _columnsDiffer: IterableDiffer<any>;
+  protected _columnsDiffer!: IterableDiffer<any>;
 
   constructor(...args: unknown[]);
   constructor() {}
@@ -205,7 +205,7 @@ export class CdkRowDef<T> extends BaseRowDef {
    * when no other when functions return true for the data.
    * For every row, there must be at least one when function that passes or an undefined to default.
    */
-  when: (index: number, rowData: T) => boolean;
+  when!: (index: number, rowData: T) => boolean;
 
   constructor(...args: unknown[]);
 
@@ -282,7 +282,7 @@ export class CdkCellOutlet implements OnDestroy {
   _viewContainer = inject(ViewContainerRef);
 
   /** The ordered list of cells to render within this outlet's view container */
-  cells: CdkCellDef[];
+  cells!: CdkCellDef[];
 
   /** The data context to be provided to each cell */
   context: any;
diff --git a/src/cdk/table/table.spec.ts b/src/cdk/table/table.spec.ts
index 99dea6982ef5..842033adad87 100644
--- a/src/cdk/table/table.spec.ts
+++ b/src/cdk/table/table.spec.ts
@@ -2209,7 +2209,7 @@ class SimpleCdkTableApp {
   columnsToRender = ['column_a', 'column_b', 'column_c'];
   contentChangedCount = 0;
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2240,7 +2240,7 @@ class CdkTableWithDifferentDataInputsApp {
   dataSource: DataSource<TestData> | Observable<TestData[]> | TestData[] | any = null;
   columnsToRender = ['column_a', 'column_b', 'column_c'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2375,7 +2375,7 @@ class WhenRowCdkTableApp {
     this.dataSource.addData();
   }
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 
   showIndexColumns() {
     const indexColumns = ['index', 'dataIndex', 'renderIndex'];
@@ -2480,7 +2480,7 @@ class WhenRowWithoutDefaultCdkTableApp {
   isIndex1 = (index: number, _rowData: TestData) => index == 1;
   hasC3 = (_index: number, rowData: TestData) => rowData.c == 'c_3';
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2524,7 +2524,7 @@ class WhenRowMultipleDefaultsCdkTableApp {
   columnsToRender = ['column_a', 'column_b', 'column_c'];
   hasC3 = (_index: number, rowData: TestData) => rowData.c == 'c_3';
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2542,10 +2542,10 @@ class WhenRowMultipleDefaultsCdkTableApp {
   imports: [CdkTableModule],
 })
 class DynamicDataSourceCdkTableApp {
-  dataSource: FakeDataSource;
+  dataSource!: FakeDataSource;
   columnsToRender = ['column_a'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2573,7 +2573,7 @@ class TrackByCdkTableApp {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a', 'column_b'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 
   trackBy = (index: number, item: TestData) => {
     switch (this.trackByStrategy) {
@@ -2656,7 +2656,7 @@ class StickyFlexLayoutCdkTableApp extends StickyPositioningListenerTest {
   dataSource = new FakeDataSource();
   columns = ['column-1', 'column-2', 'column-3', 'column-4', 'column-5', 'column-6'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 
   dir: Direction = 'ltr';
   stickyHeaders: string[] = [];
@@ -2713,7 +2713,7 @@ class StickyNativeLayoutCdkTableApp extends StickyPositioningListenerTest {
   dataSource = new FakeDataSource();
   columns = ['column-1', 'column-2', 'column-3', 'column-4', 'column-5', 'column-6'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 
   stickyHeaders: string[] = [];
   stickyFooters: string[] = [];
@@ -2745,7 +2745,7 @@ class DynamicColumnDefinitionsCdkTableApp {
   dynamicColumns: any[] = [];
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2766,7 +2766,7 @@ class CustomRoleCdkTableApp {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2787,7 +2787,7 @@ class CrazyColumnNameCdkTableApp {
   dataSource = new FakeDataSource();
   columnsToRender = ['crazy-column-NAME-1!@#$%^-_&*()2'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -2846,7 +2846,7 @@ class MissingColumnDefCdkTableApp {
   imports: [CdkTableModule],
 })
 class MissingColumnDefAfterRenderCdkTableApp implements AfterViewInit {
-  dataSource: FakeDataSource;
+  dataSource!: FakeDataSource;
   displayedColumns: string[] = [];
   cdr = inject(ChangeDetectorRef);
 
@@ -2945,7 +2945,7 @@ class MissingFooterRowDefCdkTableApp {
   imports: [CdkTableModule],
 })
 class UndefinedColumnsCdkTableApp {
-  undefinedColumns: string[];
+  undefinedColumns: string[] | undefined;
   dataSource = new FakeDataSource();
 }
 
@@ -3006,15 +3006,15 @@ class RowContextCdkTableApp {
   imports: [CdkTableModule],
 })
 class WrapperCdkTableApp<T> implements AfterContentInit {
-  @ContentChildren(CdkColumnDef, {descendants: false}) columnDefs: QueryList<CdkColumnDef>;
-  @ContentChild(CdkHeaderRowDef) headerRowDef: CdkHeaderRowDef;
-  @ContentChildren(CdkRowDef, {descendants: false}) rowDefs: QueryList<CdkRowDef<T>>;
-  @ContentChild(CdkNoDataRow) noDataRow: CdkNoDataRow;
+  @ContentChildren(CdkColumnDef, {descendants: false}) columnDefs!: QueryList<CdkColumnDef>;
+  @ContentChild(CdkHeaderRowDef) headerRowDef!: CdkHeaderRowDef;
+  @ContentChildren(CdkRowDef, {descendants: false}) rowDefs!: QueryList<CdkRowDef<T>>;
+  @ContentChild(CdkNoDataRow) noDataRow!: CdkNoDataRow;
 
-  @ViewChild(CdkTable, {static: true}) table: CdkTable<T>;
+  @ViewChild(CdkTable, {static: true}) table!: CdkTable<T>;
 
-  @Input() columns: string[];
-  @Input() dataSource: DataSource<T>;
+  @Input() columns!: string[];
+  @Input() dataSource!: DataSource<T>;
 
   ngAfterContentInit() {
     // Register the content's column, row, and header row definitions.
@@ -3092,7 +3092,7 @@ class NativeHtmlTableApp {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a', 'column_b', 'column_c'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -3171,7 +3171,7 @@ class NativeTableWithNoHeaderOrFooterRows {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a', 'column_b', 'column_c'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -3193,7 +3193,7 @@ class NativeHtmlTableWithCaptionApp {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -3222,7 +3222,7 @@ class NativeHtmlTableWithColgroupAndCol {
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a', 'column_b'];
 
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
 }
 
 @Component({
@@ -3276,7 +3276,7 @@ class TableWithIndirectDescendantDefs {
   imports: [CdkTableModule],
 })
 class NativeHtmlTableAppOnPush {
-  @Input() dataSource: FakeDataSource;
+  @Input() dataSource!: FakeDataSource;
   columnsToRender = ['column_a', 'column_b', 'column_c'];
 }
 
@@ -3327,8 +3327,8 @@ class WrapNativeHtmlTableAppOnPush {
   `,
 })
 class TableWithVirtualScroll {
-  @ViewChild(CdkTable) table: CdkTable<TestData>;
-  @ViewChild(CdkVirtualScrollViewport) viewport: CdkVirtualScrollViewport;
+  @ViewChild(CdkTable) table!: CdkTable<TestData>;
+  @ViewChild(CdkVirtualScrollViewport) viewport!: CdkVirtualScrollViewport;
   dataSource = new FakeDataSource();
   columnsToRender = ['column_a', 'column_b', 'column_c'];
   isFixedLayout = signal(true);
diff --git a/src/cdk/table/table.ts b/src/cdk/table/table.ts
index a50673835f02..8d1781ae5be4 100644
--- a/src/cdk/table/table.ts
+++ b/src/cdk/table/table.ts
@@ -297,7 +297,7 @@ export class CdkTable<T>
   protected readonly _elementRef = inject(ElementRef);
   protected readonly _dir = inject(Directionality, {optional: true});
   private _platform = inject(Platform);
-  protected _viewRepeater: _ViewRepeater<T, RenderRow<T>, RowContext<T>>;
+  protected _viewRepeater!: _ViewRepeater<T, RenderRow<T>, RowContext<T>>;
   private readonly _viewportRuler = inject(ViewportRuler);
   private _injector = inject(Injector);
   private _virtualScrollViewport = inject(CDK_VIRTUAL_SCROLL_VIEWPORT, {
@@ -322,10 +322,10 @@ export class CdkTable<T>
   private readonly _onDestroy = new Subject<void>();
 
   /** List of the rendered rows as identified by their `RenderRow` object. */
-  private _renderRows: RenderRow<T>[];
+  private _renderRows!: RenderRow<T>[];
 
   /** Subscription that listens for the data provided by the data source. */
-  private _renderChangeSubscription: Subscription | null;
+  private _renderChangeSubscription: Subscription | null = null;
 
   /**
    * Map of all the user's defined columns (header, data, and footer cell template) identified by
@@ -338,27 +338,27 @@ export class CdkTable<T>
    * Set of all row definitions that can be used by this table. Populated by the rows gathered by
    * using `ContentChildren` as well as any custom row definitions added to `_customRowDefs`.
    */
-  private _rowDefs: CdkRowDef<T>[];
+  private _rowDefs!: CdkRowDef<T>[];
 
   /**
    * Set of all header row definitions that can be used by this table. Populated by the rows
    * gathered by using `ContentChildren` as well as any custom row definitions added to
    * `_customHeaderRowDefs`.
    */
-  private _headerRowDefs: CdkHeaderRowDef[];
+  private _headerRowDefs!: CdkHeaderRowDef[];
 
   /**
    * Set of all row definitions that can be used by this table. Populated by the rows gathered by
    * using `ContentChildren` as well as any custom row definitions added to
    * `_customFooterRowDefs`.
    */
-  private _footerRowDefs: CdkFooterRowDef[];
+  private _footerRowDefs!: CdkFooterRowDef[];
 
   /** Differ used to find the changes in the data provided by the data source. */
   private _dataDiffer: IterableDiffer<RenderRow<T>>;
 
   /** Stores the row definition that does not have a when predicate. */
-  private _defaultRowDef: CdkRowDef<T> | null;
+  private _defaultRowDef: CdkRowDef<T> | null = null;
 
   /**
    * Column definitions that were defined outside of the direct content children of the table.
@@ -389,7 +389,7 @@ export class CdkTable<T>
   private _customFooterRowDefs = new Set<CdkFooterRowDef>();
 
   /** No data row that was defined outside of the direct content children of the table. */
-  private _customNoDataRow: CdkNoDataRow | null;
+  private _customNoDataRow: CdkNoDataRow | null = null;
 
   /**
    * Whether the header row definition has been changed. Triggers an update to the header row after
@@ -438,7 +438,7 @@ export class CdkTable<T>
    * Utility class that is responsible for applying the appropriate sticky positioning styles to
    * the table's rows and cells.
    */
-  private _stickyStyler: StickyStyler;
+  private _stickyStyler!: StickyStyler;
 
   /**
    * CSS class added to any row or cell that has sticky positioning applied. May be overridden by
@@ -509,7 +509,7 @@ export class CdkTable<T>
     }
     this._trackByFn = fn;
   }
-  private _trackByFn: TrackByFunction<T>;
+  private _trackByFn!: TrackByFunction<T>;
 
   /**
    * The table's source of data, which can be provided in three ways (in order of complexity):
@@ -541,7 +541,7 @@ export class CdkTable<T>
       this._changeDetectorRef.markForCheck();
     }
   }
-  private _dataSource: CdkTableDataSourceInput<T>;
+  private _dataSource!: CdkTableDataSourceInput<T>;
   /** Emits when the data source changes. */
   readonly _dataSourceChanges = new Subject<CdkTableDataSourceInput<T>>();
   /** Observable that emits the data source's complete data set. */
@@ -613,34 +613,34 @@ export class CdkTable<T>
   });
 
   // Outlets in the table's template where the header, data rows, and footer will be inserted.
-  _rowOutlet: DataRowOutlet;
-  _headerRowOutlet: HeaderRowOutlet;
-  _footerRowOutlet: FooterRowOutlet;
-  _noDataRowOutlet: NoDataRowOutlet;
+  _rowOutlet!: DataRowOutlet;
+  _headerRowOutlet!: HeaderRowOutlet;
+  _footerRowOutlet!: FooterRowOutlet;
+  _noDataRowOutlet!: NoDataRowOutlet;
 
   /**
    * The column definitions provided by the user that contain what the header, data, and footer
    * cells should render for each column.
    */
-  @ContentChildren(CdkColumnDef, {descendants: true}) _contentColumnDefs: QueryList<CdkColumnDef>;
+  @ContentChildren(CdkColumnDef, {descendants: true}) _contentColumnDefs!: QueryList<CdkColumnDef>;
 
   /** Set of data row definitions that were provided to the table as content children. */
-  @ContentChildren(CdkRowDef, {descendants: true}) _contentRowDefs: QueryList<CdkRowDef<T>>;
+  @ContentChildren(CdkRowDef, {descendants: true}) _contentRowDefs!: QueryList<CdkRowDef<T>>;
 
   /** Set of header row definitions that were provided to the table as content children. */
   @ContentChildren(CdkHeaderRowDef, {
     descendants: true,
   })
-  _contentHeaderRowDefs: QueryList<CdkHeaderRowDef>;
+  _contentHeaderRowDefs!: QueryList<CdkHeaderRowDef>;
 
   /** Set of footer row definitions that were provided to the table as content children. */
   @ContentChildren(CdkFooterRowDef, {
     descendants: true,
   })
-  _contentFooterRowDefs: QueryList<CdkFooterRowDef>;
+  _contentFooterRowDefs!: QueryList<CdkFooterRowDef>;
 
   /** Row definition that will only be rendered if there's no data in the table. */
-  @ContentChild(CdkNoDataRow) _noDataRow: CdkNoDataRow;
+  @ContentChild(CdkNoDataRow) _noDataRow!: CdkNoDataRow;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/table/text-column.ts b/src/cdk/table/text-column.ts
index bfe9e0c04fc2..a87ab57bddd2 100644
--- a/src/cdk/table/text-column.ts
+++ b/src/cdk/table/text-column.ts
@@ -71,13 +71,13 @@ export class CdkTextColumn<T> implements OnDestroy, OnInit {
     // available. In that case, we defer the synchronization until "ngOnInit" fires.
     this._syncColumnDefName();
   }
-  _name: string;
+  _name!: string;
 
   /**
    * Text label that should be used for the column header. If this property is not
    * set, the header text will default to the column name with its first letter capitalized.
    */
-  @Input() headerText: string;
+  @Input() headerText!: string;
 
   /**
    * Accessor function to retrieve the data rendered for each cell. If this
@@ -85,13 +85,13 @@ export class CdkTextColumn<T> implements OnDestroy, OnInit {
    * the column's name. For example, if the column is named `id`, then the rendered value will be
    * value defined by the data's `id` property.
    */
-  @Input() dataAccessor: (data: T, name: string) => string;
+  @Input() dataAccessor!: (data: T, name: string) => string;
 
   /** Alignment of the cell values. */
   @Input() justify: 'start' | 'end' | 'center' = 'start';
 
   /** @docs-private */
-  @ViewChild(CdkColumnDef, {static: true}) columnDef: CdkColumnDef;
+  @ViewChild(CdkColumnDef, {static: true}) columnDef!: CdkColumnDef;
 
   /**
    * The column cell is provided to the column during `ngOnInit` with a static query.
@@ -100,7 +100,7 @@ export class CdkTextColumn<T> implements OnDestroy, OnInit {
    * component.
    * @docs-private
    */
-  @ViewChild(CdkCellDef, {static: true}) cell: CdkCellDef;
+  @ViewChild(CdkCellDef, {static: true}) cell!: CdkCellDef;
 
   /**
    * The column headerCell is provided to the column during `ngOnInit` with a static query.
@@ -109,7 +109,7 @@ export class CdkTextColumn<T> implements OnDestroy, OnInit {
    * component.
    * @docs-private
    */
-  @ViewChild(CdkHeaderCellDef, {static: true}) headerCell: CdkHeaderCellDef;
+  @ViewChild(CdkHeaderCellDef, {static: true}) headerCell!: CdkHeaderCellDef;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/testing/component-harness.ts b/src/cdk/testing/component-harness.ts
index 646ac6ef1edc..8a6ed5ca4ebf 100644
--- a/src/cdk/testing/component-harness.ts
+++ b/src/cdk/testing/component-harness.ts
@@ -609,7 +609,16 @@ export class HarnessPredicate<T extends ComponentHarness> {
     public harnessType: ComponentHarnessConstructor<T>,
     options: BaseHarnessFilters,
   ) {
-    this._addBaseOptions(options);
+    this._ancestor = options.ancestor || '';
+    if (this._ancestor) {
+      this._descriptions.push(`has ancestor matching selector "${this._ancestor}"`);
+    }
+    const selector = options.selector;
+    if (selector !== undefined) {
+      this.add(`host matches selector "${selector}"`, async item => {
+        return (await item.host()).matchesSelector(selector);
+      });
+    }
   }
 
   /**
@@ -714,20 +723,6 @@ export class HarnessPredicate<T extends ComponentHarness> {
 
     return result.join(', ');
   }
-
-  /** Adds base options common to all harness types. */
-  private _addBaseOptions(options: BaseHarnessFilters) {
-    this._ancestor = options.ancestor || '';
-    if (this._ancestor) {
-      this._descriptions.push(`has ancestor matching selector "${this._ancestor}"`);
-    }
-    const selector = options.selector;
-    if (selector !== undefined) {
-      this.add(`host matches selector "${selector}"`, async item => {
-        return (await item.host()).matchesSelector(selector);
-      });
-    }
-  }
 }
 
 /** Represent a value as a string for the purpose of logging. */
diff --git a/src/cdk/text-field/autofill.zone.spec.ts b/src/cdk/text-field/autofill.zone.spec.ts
index e3cfd319d6f9..cc0e305367f2 100644
--- a/src/cdk/text-field/autofill.zone.spec.ts
+++ b/src/cdk/text-field/autofill.zone.spec.ts
@@ -48,7 +48,7 @@ describe('AutofillMonitor Zone.js integration', () => {
 })
 class Inputs {
   // Cast to `any` so we can stub out some methods in the tests.
-  @ViewChild('input1') input1: ElementRef<any>;
-  @ViewChild('input2') input2: ElementRef<any>;
-  @ViewChild('input3') input3: ElementRef<any>;
+  @ViewChild('input1') input1!: ElementRef<any>;
+  @ViewChild('input2') input2!: ElementRef<any>;
+  @ViewChild('input3') input3!: ElementRef<any>;
 }
diff --git a/src/cdk/text-field/autosize.ts b/src/cdk/text-field/autosize.ts
index 09ae53c4f711..81ee7726a75f 100644
--- a/src/cdk/text-field/autosize.ts
+++ b/src/cdk/text-field/autosize.ts
@@ -52,8 +52,8 @@ export class CdkTextareaAutosize implements AfterViewInit, DoCheck, OnDestroy {
   private readonly _destroyed = new Subject<void>();
   private _listenerCleanups: (() => void)[] | undefined;
 
-  private _minRows: number;
-  private _maxRows: number;
+  private _minRows!: number;
+  private _maxRows!: number;
   private _enabled: boolean = true;
 
   /**
@@ -122,7 +122,7 @@ export class CdkTextareaAutosize implements AfterViewInit, DoCheck, OnDestroy {
   /** Used to reference correct document/window */
   protected _document = inject(DOCUMENT);
 
-  private _hasFocus: boolean;
+  private _hasFocus = false;
 
   private _isViewInited = false;
 
diff --git a/src/cdk/tree/control/base-tree-control.ts b/src/cdk/tree/control/base-tree-control.ts
index d0cb38b5c3ad..c22ddc7ec7f7 100644
--- a/src/cdk/tree/control/base-tree-control.ts
+++ b/src/cdk/tree/control/base-tree-control.ts
@@ -23,7 +23,7 @@ export abstract class BaseTreeControl<T, K = T> implements TreeControl<T, K> {
   abstract expandAll(): void;
 
   /** Saved data node for `expandAll` action. */
-  dataNodes: T[];
+  dataNodes!: T[];
 
   /** A selection model with multi-selection to track expansion status. */
   expansionModel: SelectionModel<K> = new SelectionModel<K>(true);
@@ -37,16 +37,16 @@ export abstract class BaseTreeControl<T, K = T> implements TreeControl<T, K> {
   trackBy?: (dataNode: T) => K;
 
   /** Get depth of a given data node, return the level number. This is for flat tree node. */
-  getLevel: (dataNode: T) => number;
+  getLevel!: (dataNode: T) => number;
 
   /**
    * Whether the data node is expandable. Returns true if expandable.
    * This is for flat tree node.
    */
-  isExpandable: (dataNode: T) => boolean;
+  isExpandable!: (dataNode: T) => boolean;
 
   /** Gets a stream that emits whenever the given data node's children change. */
-  getChildren: (dataNode: T) => Observable<T[]> | T[] | undefined | null;
+  getChildren!: (dataNode: T) => Observable<T[]> | T[] | undefined | null;
 
   /** Toggles one single data node's expanded/collapsed state. */
   toggle(dataNode: T): void {
diff --git a/src/cdk/tree/nested-node.ts b/src/cdk/tree/nested-node.ts
index 6d7a93b88264..978433b50338 100644
--- a/src/cdk/tree/nested-node.ts
+++ b/src/cdk/tree/nested-node.ts
@@ -45,10 +45,10 @@ export class CdkNestedTreeNode<T, K = T>
   protected _differs = inject(IterableDiffers);
 
   /** Differ used to find the changes in the data provided by the data source. */
-  private _dataDiffer: IterableDiffer<T>;
+  private _dataDiffer!: IterableDiffer<T>;
 
   /** The children data dataNodes of current node. They will be placed in `CdkTreeNodeOutlet`. */
-  protected _children: T[];
+  protected _children!: T[];
 
   /** The children node placeholder. */
   @ContentChildren(CdkTreeNodeOutlet, {
@@ -56,7 +56,7 @@ export class CdkNestedTreeNode<T, K = T>
     // indirect descendants if it's left as false.
     descendants: true,
   })
-  nodeOutlet: QueryList<CdkTreeNodeOutlet>;
+  nodeOutlet!: QueryList<CdkTreeNodeOutlet>;
 
   constructor(...args: unknown[]);
 
diff --git a/src/cdk/tree/node.ts b/src/cdk/tree/node.ts
index 79356c0bf668..738ba8627479 100644
--- a/src/cdk/tree/node.ts
+++ b/src/cdk/tree/node.ts
@@ -14,7 +14,7 @@ export class CdkTreeNodeOutletContext<T> {
   $implicit: T;
 
   /** Depth of the node. */
-  level: number;
+  level!: number;
 
   /** Index location of the node. */
   index?: number;
@@ -46,7 +46,7 @@ export class CdkTreeNodeDef<T> {
    * For every node, there must be at least one when function that passes or an undefined to
    * default.
    */
-  when: (index: number, nodeData: T) => boolean;
+  when!: (index: number, nodeData: T) => boolean;
 
   constructor(...args: unknown[]);
   constructor() {}
diff --git a/src/cdk/tree/padding.ts b/src/cdk/tree/padding.ts
index 4dac40d9870c..ded80bb31ad1 100644
--- a/src/cdk/tree/padding.ts
+++ b/src/cdk/tree/padding.ts
@@ -29,7 +29,7 @@ export class CdkTreeNodePadding<T, K = T> implements OnDestroy {
   private _dir = inject(Directionality, {optional: true});
 
   /** Current padding value applied to the element. Used to avoid unnecessarily hitting the DOM. */
-  private _currentPadding: string | null;
+  private _currentPadding: string | null = null;
 
   /** Subject that emits when the component has been destroyed. */
   private readonly _destroyed = new Subject<void>();
@@ -45,7 +45,7 @@ export class CdkTreeNodePadding<T, K = T> implements OnDestroy {
   set level(value: number) {
     this._setLevelInput(value);
   }
-  _level: number;
+  _level!: number;
 
   /**
    * The indent for each level. Can be a number or a CSS string.
diff --git a/src/cdk/tree/tree-using-legacy-key-manager.spec.ts b/src/cdk/tree/tree-using-legacy-key-manager.spec.ts
index fecb0b756ce6..1cadb181365d 100644
--- a/src/cdk/tree/tree-using-legacy-key-manager.spec.ts
+++ b/src/cdk/tree/tree-using-legacy-key-manager.spec.ts
@@ -83,6 +83,6 @@ class SimpleCdkTreeApp {
 
   dataSource = of([new MinimalTestData('apple'), new MinimalTestData('banana')]);
 
-  @ViewChild('tree', {read: ElementRef}) tree: ElementRef<HTMLElement>;
-  @ViewChildren('node') treeNodes: QueryList<ElementRef<HTMLElement>>;
+  @ViewChild('tree', {read: ElementRef}) tree!: ElementRef<HTMLElement>;
+  @ViewChildren('node') treeNodes!: QueryList<ElementRef<HTMLElement>>;
 }
diff --git a/src/cdk/tree/tree-with-tree-control.spec.ts b/src/cdk/tree/tree-with-tree-control.spec.ts
index 329645f412de..ce44de525a9f 100644
--- a/src/cdk/tree/tree-with-tree-control.spec.ts
+++ b/src/cdk/tree/tree-with-tree-control.spec.ts
@@ -1451,8 +1451,8 @@ class SimpleCdkTreeApp {
   dataSource = new FakeDataSource(this.treeControl);
   indent: number | string = 28;
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
-  @ViewChildren(CdkTreeNodePadding) paddingNodes: QueryList<CdkTreeNodePadding<TestData>>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
+  @ViewChildren(CdkTreeNodePadding) paddingNodes!: QueryList<CdkTreeNodePadding<TestData>>;
 }
 
 @Component({
@@ -1489,7 +1489,7 @@ class NestedCdkTreeApp {
 
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1515,7 +1515,7 @@ class StaticNestedCdkTreeApp {
 
   dataSource: FakeDataSource;
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 
   constructor() {
     const dataSource = new FakeDataSource(this.treeControl);
@@ -1552,7 +1552,7 @@ class WhenNodeNestedCdkTreeApp {
 
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1576,7 +1576,7 @@ class CdkTreeAppWithToggle {
   treeControl: TreeControl<TestData> = new FlatTreeControl(this.getLevel, this.isExpandable);
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1604,7 +1604,7 @@ class NestedCdkTreeAppWithToggle {
   treeControl: TreeControl<TestData> = new NestedTreeControl(this.getChildren);
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1633,7 +1633,7 @@ class WhenNodeCdkTreeApp {
 
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1660,7 +1660,7 @@ class ArrayDataSourceCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1687,7 +1687,7 @@ class ObservableDataSourceCdkTreeApp {
     return this.dataSource._dataChange;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1712,7 +1712,7 @@ class ArrayDataSourceNestedCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1737,7 +1737,7 @@ class ObservableDataSourceNestedCdkTreeApp {
     return this.dataSource._dataChange;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1763,7 +1763,7 @@ class DepthNestedCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1796,7 +1796,7 @@ class CdkTreeAppWithTrackBy {
   treeControl: TreeControl<TestData> = new FlatTreeControl(this.getLevel, this.isExpandable);
   dataSource = new FakeDataSource(this.treeControl);
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1834,5 +1834,5 @@ class NestedCdkTreeAppWithTrackBy {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
diff --git a/src/cdk/tree/tree.spec.ts b/src/cdk/tree/tree.spec.ts
index d4f8806c14e9..7513863c9f17 100644
--- a/src/cdk/tree/tree.spec.ts
+++ b/src/cdk/tree/tree.spec.ts
@@ -1698,8 +1698,8 @@ class SimpleCdkTreeApp {
   dataSource = new FakeDataSource();
   indent: number | string = 28;
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
-  @ViewChildren(CdkTreeNodePadding) paddingNodes: QueryList<CdkTreeNodePadding<TestData>>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
+  @ViewChildren(CdkTreeNodePadding) paddingNodes!: QueryList<CdkTreeNodePadding<TestData>>;
 }
 
 @Component({
@@ -1738,7 +1738,7 @@ class NestedCdkTreeApp {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1762,7 +1762,7 @@ class StaticNestedCdkTreeApp {
 
   dataSource: FakeDataSource;
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 
   constructor() {
     const dataSource = new FakeDataSource();
@@ -1798,7 +1798,7 @@ class WhenNodeNestedCdkTreeApp {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1823,7 +1823,7 @@ class CdkTreeAppWithToggle {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1854,7 +1854,7 @@ class NestedCdkTreeAppWithToggle {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1884,7 +1884,7 @@ class WhenNodeCdkTreeApp {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1911,7 +1911,7 @@ class ArrayDataSourceCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 
   cdr = inject(ChangeDetectorRef);
 
@@ -1946,7 +1946,7 @@ class ObservableDataSourceCdkTreeApp {
     return this.dataSource._dataChange;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1970,7 +1970,7 @@ class ArrayDataSourceNestedCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -1994,7 +1994,7 @@ class ObservableDataSourceNestedCdkTreeApp {
     return this.dataSource._dataChange;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -2019,7 +2019,7 @@ class DepthNestedCdkTreeApp {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -2052,7 +2052,7 @@ class CdkTreeAppWithTrackBy {
 
   dataSource = new FakeDataSource();
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 @Component({
@@ -2089,7 +2089,7 @@ class NestedCdkTreeAppWithTrackBy {
     return this.dataSource.data;
   }
 
-  @ViewChild(CdkTree) tree: CdkTree<TestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<TestData>;
 }
 
 class MinimalTestData {
@@ -2121,8 +2121,8 @@ class TypeaheadLabelFlatTreeWithThreeNodes {
     new MinimalTestData('cherry', 'typeahead'),
   ]);
 
-  @ViewChild('tree', {read: ElementRef}) tree: ElementRef<HTMLElement>;
-  @ViewChildren('node') treeNodes: QueryList<ElementRef<HTMLElement>>;
+  @ViewChild('tree', {read: ElementRef}) tree!: ElementRef<HTMLElement>;
+  @ViewChildren('node') treeNodes!: QueryList<ElementRef<HTMLElement>>;
 }
 
 @Component({
@@ -2145,8 +2145,8 @@ class FlatTreeWithThreeNodes {
     new MinimalTestData('cherry'),
   ]);
 
-  @ViewChild('tree', {read: ElementRef}) tree: ElementRef<HTMLElement>;
-  @ViewChildren('node') treeNodes: QueryList<ElementRef<HTMLElement>>;
+  @ViewChild('tree', {read: ElementRef}) tree!: ElementRef<HTMLElement>;
+  @ViewChildren('node') treeNodes!: QueryList<ElementRef<HTMLElement>>;
 }
 
 @Component({
@@ -2165,7 +2165,7 @@ class FlatTreeWithThreeNodes {
 class IsExpandableOrderingTest {
   getChildren = (node: MinimalTestData) => node.children;
 
-  @ViewChild(CdkTree) tree: CdkTree<MinimalTestData>;
+  @ViewChild(CdkTree) tree!: CdkTree<MinimalTestData>;
 
   dataSource: MinimalTestData[];
 
diff --git a/src/cdk/tree/tree.ts b/src/cdk/tree/tree.ts
index 8f086ee758c9..95913a582078 100644
--- a/src/cdk/tree/tree.ts
+++ b/src/cdk/tree/tree.ts
@@ -134,13 +134,13 @@ export class CdkTree<T, K = T>
   private readonly _onDestroy = new Subject<void>();
 
   /** Differ used to find the changes in the data provided by the data source. */
-  private _dataDiffer: IterableDiffer<T>;
+  private _dataDiffer!: IterableDiffer<T>;
 
   /** Stores the node definition that does not have a when predicate. */
-  private _defaultNodeDef: CdkTreeNodeDef<T> | null;
+  private _defaultNodeDef: CdkTreeNodeDef<T> | null = null;
 
   /** Data subscription */
-  private _dataSubscription: Subscription | null;
+  private _dataSubscription: Subscription | undefined;
 
   /** Level of nodes */
   private _levels: Map<K, number> = new Map<K, number>();
@@ -172,7 +172,7 @@ export class CdkTree<T, K = T>
       this._switchDataSource(dataSource);
     }
   }
-  private _dataSource: DataSource<T> | Observable<T[]> | T[];
+  private _dataSource!: DataSource<T> | Observable<T[]> | T[];
 
   /**
    * The tree controller
@@ -205,7 +205,7 @@ export class CdkTree<T, K = T>
    * relative to the function to know if a node should be added/removed/moved.
    * Accepts a function that takes two parameters, `index` and `item`.
    */
-  @Input() trackBy: TrackByFunction<T>;
+  @Input() trackBy!: TrackByFunction<T>;
 
   /**
    * Given a data node, determines the key by which we determine whether or not this node is expanded.
@@ -213,7 +213,7 @@ export class CdkTree<T, K = T>
   @Input() expansionKey?: (dataNode: T) => K;
 
   // Outlets within the tree's template where the dataNodes will be inserted.
-  @ViewChild(CdkTreeNodeOutlet, {static: true}) _nodeOutlet: CdkTreeNodeOutlet;
+  @ViewChild(CdkTreeNodeOutlet, {static: true}) _nodeOutlet!: CdkTreeNodeOutlet;
 
   /** The tree node template for the tree */
   @ContentChildren(CdkTreeNodeDef, {
@@ -221,7 +221,7 @@ export class CdkTree<T, K = T>
     // indirect descendants if it's left as false.
     descendants: true,
   })
-  _nodeDefs: QueryList<CdkTreeNodeDef<T>>;
+  _nodeDefs!: QueryList<CdkTreeNodeDef<T>>;
 
   // TODO(tinayuangao): Setup a listener for scrolling, emit the calculated view to viewChange.
   //     Remove the MAX_VALUE in viewChange
@@ -264,7 +264,7 @@ export class CdkTree<T, K = T>
   private _keyManagerFactory = inject(TREE_KEY_MANAGER) as TreeKeyManagerFactory<CdkTreeNode<T, K>>;
 
   /** The key manager for this tree. Handles focus and activation based on user keyboard input. */
-  _keyManager: TreeKeyManagerStrategy<CdkTreeNode<T, K>>;
+  _keyManager!: TreeKeyManagerStrategy<CdkTreeNode<T, K>>;
   private _viewInit = false;
 
   constructor(...args: unknown[]);
@@ -294,10 +294,8 @@ export class CdkTree<T, K = T>
       (this.dataSource as DataSource<T>).disconnect(this);
     }
 
-    if (this._dataSubscription) {
-      this._dataSubscription.unsubscribe();
-      this._dataSubscription = null;
-    }
+    this._dataSubscription?.unsubscribe();
+    this._dataSubscription = undefined;
 
     // In certain tests, the tree might be destroyed before this is initialized
     // in `ngAfterContentInit`.
@@ -351,10 +349,8 @@ export class CdkTree<T, K = T>
       (this.dataSource as DataSource<T>).disconnect(this);
     }
 
-    if (this._dataSubscription) {
-      this._dataSubscription.unsubscribe();
-      this._dataSubscription = null;
-    }
+    this._dataSubscription?.unsubscribe();
+    this._dataSubscription = undefined;
 
     // Remove the all dataNodes if there is now no data source
     if (!dataSource) {
@@ -1264,13 +1260,13 @@ export class CdkTreeNode<T, K = T> implements OnDestroy, OnInit, TreeKeyManagerI
    * Whether or not this node is disabled. If it's disabled, then the user won't be able to focus
    * or activate this node.
    */
-  @Input({transform: booleanAttribute}) isDisabled: boolean;
+  @Input({transform: booleanAttribute}) isDisabled: boolean = false;
 
   /**
    * The text used to locate this item during typeahead. If not specified, the `textContent` will
    * will be used.
    */
-  @Input('cdkTreeNodeTypeaheadLabel') typeaheadLabel: string | null;
+  @Input('cdkTreeNodeTypeaheadLabel') typeaheadLabel: string | null = null;
 
   getLabel(): string {
     return this.typeaheadLabel || this._elementRef.nativeElement.textContent?.trim() || '';
@@ -1305,7 +1301,7 @@ export class CdkTreeNode<T, K = T> implements OnDestroy, OnInit, TreeKeyManagerI
    * (e.g. menu, dialog).
    */
   private _shouldFocus = true;
-  private _parentNodeAriaLevel: number;
+  private _parentNodeAriaLevel!: number;
 
   /** The tree node's data. */
   get data(): T {
@@ -1317,7 +1313,7 @@ export class CdkTreeNode<T, K = T> implements OnDestroy, OnInit, TreeKeyManagerI
       this._dataChanges.next();
     }
   }
-  protected _data: T;
+  protected _data!: T;
 
   /* If leaf node, return true to not assign aria-expanded attribute */
   get isLeafNode(): boolean {
diff --git a/src/cdk/tsconfig.json b/src/cdk/tsconfig.json
index 52b341bde973..8a9bdb848d33 100644
--- a/src/cdk/tsconfig.json
+++ b/src/cdk/tsconfig.json
@@ -4,6 +4,7 @@
   "compilerOptions": {
     "rootDir": "..",
     "baseUrl": ".",
+    "strictPropertyInitialization": true,
     "paths": {
       "@angular/cdk/*": ["./*"]
     }