diff --git a/packages/happy-dom/src/event/Event.ts b/packages/happy-dom/src/event/Event.ts
index 8b0634ded..c039f9b68 100644
--- a/packages/happy-dom/src/event/Event.ts
+++ b/packages/happy-dom/src/event/Event.ts
@@ -12,9 +12,9 @@ import IDocument from '../nodes/document/IDocument.js';
  * Event.
  */
 export default class Event {
-	public composed = false;
-	public bubbles = false;
-	public cancelable = false;
+	public composed: boolean;
+	public bubbles: boolean;
+	public cancelable: boolean;
 	public defaultPrevented = false;
 	public eventPhase: EventPhaseEnum = EventPhaseEnum.none;
 	public _immediatePropagationStopped = false;
@@ -22,7 +22,7 @@ export default class Event {
 	public _target: IEventTarget = null;
 	public _currentTarget: IEventTarget = null;
 	public timeStamp: number = performance.now();
-	public type: string = null;
+	public type: string;
 	public _isInPassiveEventListener = false;
 	public NONE = EventPhaseEnum.none;
 	public CAPTURING_PHASE = EventPhaseEnum.capturing;
@@ -35,14 +35,12 @@ export default class Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IEventInit = null) {
+	constructor(type: string, eventInit: IEventInit | null = null) {
 		this.type = type;
 
-		if (eventInit) {
-			this.bubbles = eventInit.bubbles || false;
-			this.cancelable = eventInit.cancelable || false;
-			this.composed = eventInit.composed || false;
-		}
+		this.bubbles = eventInit?.bubbles ?? false;
+		this.cancelable = eventInit?.cancelable ?? false;
+		this.composed = eventInit?.composed ?? false;
 	}
 
 	/**
diff --git a/packages/happy-dom/src/event/UIEvent.ts b/packages/happy-dom/src/event/UIEvent.ts
index 6e874aa3b..1fc859f16 100644
--- a/packages/happy-dom/src/event/UIEvent.ts
+++ b/packages/happy-dom/src/event/UIEvent.ts
@@ -10,12 +10,12 @@ export default class UIEvent extends Event {
 	public static CAPTURING_PHASE = 1;
 	public static AT_TARGET = 2;
 	public static BUBBLING_PHASE = 3;
-	public readonly detail: number = 0;
+	public readonly detail: number;
 	public readonly layerX: number = 0;
 	public readonly layerY: number = 0;
 	public readonly pageX: number = 0;
 	public readonly pageY: number = 0;
-	public readonly view: IWindow = null;
+	public readonly view: IWindow | null;
 
 	/**
 	 * Constructor.
@@ -23,12 +23,10 @@ export default class UIEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IUIEventInit = null) {
+	constructor(type: string, eventInit: IUIEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.detail = eventInit.detail !== undefined ? eventInit.detail : 0;
-			this.view = eventInit.view || null;
-		}
+		this.detail = eventInit?.detail ?? 0;
+		this.view = eventInit?.view ?? null;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/AnimationEvent.ts b/packages/happy-dom/src/event/events/AnimationEvent.ts
index 771dc1fd1..669e26638 100644
--- a/packages/happy-dom/src/event/events/AnimationEvent.ts
+++ b/packages/happy-dom/src/event/events/AnimationEvent.ts
@@ -5,9 +5,9 @@ import IAnimationEventInit from './IAnimationEventInit.js';
  *
  */
 export default class AnimationEvent extends Event {
-	public animationName = '';
-	public elapsedTime = 0;
-	public pseudoElement = '';
+	public readonly animationName: string;
+	public readonly elapsedTime: number;
+	public readonly pseudoElement: string;
 
 	/**
 	 * Constructor.
@@ -15,10 +15,11 @@ export default class AnimationEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit?: IAnimationEventInit) {
+	constructor(type: string, eventInit: IAnimationEventInit | null = null) {
 		super(type, eventInit);
-		this.animationName = eventInit?.animationName || '';
-		this.elapsedTime = eventInit?.elapsedTime || 0;
-		this.pseudoElement = eventInit?.pseudoElement || '';
+
+		this.animationName = eventInit?.animationName ?? '';
+		this.elapsedTime = eventInit?.elapsedTime ?? 0;
+		this.pseudoElement = eventInit?.pseudoElement ?? '';
 	}
 }
diff --git a/packages/happy-dom/src/event/events/CustomEvent.ts b/packages/happy-dom/src/event/events/CustomEvent.ts
index 91fc93be2..0393d9709 100644
--- a/packages/happy-dom/src/event/events/CustomEvent.ts
+++ b/packages/happy-dom/src/event/events/CustomEvent.ts
@@ -5,7 +5,8 @@ import ICustomEventInit from './ICustomEventInit.js';
  *
  */
 export default class CustomEvent extends Event {
-	public detail: object = null;
+	// eslint-disable-next-line @typescript-eslint/no-explicit-any
+	public detail: any;
 
 	/**
 	 * Constructor.
@@ -13,12 +14,10 @@ export default class CustomEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: ICustomEventInit = null) {
+	constructor(type: string, eventInit: ICustomEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.detail = eventInit.detail !== undefined ? eventInit.detail : null;
-		}
+		this.detail = eventInit?.detail ?? null;
 	}
 
 	/**
diff --git a/packages/happy-dom/src/event/events/ErrorEvent.ts b/packages/happy-dom/src/event/events/ErrorEvent.ts
index e06b6e2ba..1bd1725c5 100644
--- a/packages/happy-dom/src/event/events/ErrorEvent.ts
+++ b/packages/happy-dom/src/event/events/ErrorEvent.ts
@@ -5,11 +5,11 @@ import IErrorEventInit from './IErrorEventInit.js';
  *
  */
 export default class ErrorEvent extends UIEvent {
-	public readonly message: string = '';
-	public readonly filename: string = '';
-	public readonly lineno: number = 0;
-	public readonly colno: number = 0;
-	public readonly error: Error | null = null;
+	public readonly message: string;
+	public readonly filename: string;
+	public readonly lineno: number;
+	public readonly colno: number;
+	public readonly error: Error | null;
 
 	/**
 	 * Constructor.
@@ -17,15 +17,13 @@ export default class ErrorEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IErrorEventInit = null) {
+	constructor(type: string, eventInit: IErrorEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.message = eventInit.message || '';
-			this.filename = eventInit.filename || '';
-			this.lineno = eventInit.lineno !== undefined ? eventInit.lineno : 0;
-			this.colno = eventInit.colno !== undefined ? eventInit.colno : 0;
-			this.error = eventInit.error || null;
-		}
+		this.message = eventInit?.message ?? '';
+		this.filename = eventInit?.filename ?? '';
+		this.lineno = eventInit?.lineno ?? 0;
+		this.colno = eventInit?.colno ?? 0;
+		this.error = eventInit?.error ?? null;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/FocusEvent.ts b/packages/happy-dom/src/event/events/FocusEvent.ts
index 5aef7647a..3a6493050 100644
--- a/packages/happy-dom/src/event/events/FocusEvent.ts
+++ b/packages/happy-dom/src/event/events/FocusEvent.ts
@@ -6,7 +6,7 @@ import IFocusEventInit from './IFocusEventInit.js';
  *
  */
 export default class FocusEvent extends UIEvent {
-	public readonly relatedTarget: EventTarget = null;
+	public readonly relatedTarget: EventTarget | null;
 
 	/**
 	 * Constructor.
@@ -14,11 +14,9 @@ export default class FocusEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IFocusEventInit = null) {
+	constructor(type: string, eventInit: IFocusEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.relatedTarget = eventInit.relatedTarget || null;
-		}
+		this.relatedTarget = eventInit?.relatedTarget ?? null;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/IPointerEventInit.ts b/packages/happy-dom/src/event/events/IPointerEventInit.ts
index 1ec9a1684..145da4f19 100644
--- a/packages/happy-dom/src/event/events/IPointerEventInit.ts
+++ b/packages/happy-dom/src/event/events/IPointerEventInit.ts
@@ -1,4 +1,5 @@
 import IMouseEventInit from './IMouseEventInit.js';
+import PointerEvent from './PointerEvent.js';
 
 export default interface IPointerEventInit extends IMouseEventInit {
 	pointerId?: number;
@@ -9,6 +10,10 @@ export default interface IPointerEventInit extends IMouseEventInit {
 	tiltX?: number;
 	tiltY?: number;
 	twist?: number;
+	altitudeAngle?: number;
+	azimuthAngle?: number;
 	pointerType?: string;
 	isPrimary?: boolean;
+	coalescedEvents?: PointerEvent[];
+	predictedEvents?: PointerEvent[];
 }
diff --git a/packages/happy-dom/src/event/events/IStorageEventInit.ts b/packages/happy-dom/src/event/events/IStorageEventInit.ts
index c7575f792..f0228cc94 100644
--- a/packages/happy-dom/src/event/events/IStorageEventInit.ts
+++ b/packages/happy-dom/src/event/events/IStorageEventInit.ts
@@ -3,7 +3,8 @@ import Storage from '../../storage/Storage.js';
 
 export default interface IStorageEventInit extends IEventInit {
 	key?: string;
-	newValue?: string;
 	oldValue?: string;
+	newValue?: string;
+	url?: string;
 	storageArea?: Storage;
 }
diff --git a/packages/happy-dom/src/event/events/InputEvent.ts b/packages/happy-dom/src/event/events/InputEvent.ts
index a906d4243..01c06d501 100644
--- a/packages/happy-dom/src/event/events/InputEvent.ts
+++ b/packages/happy-dom/src/event/events/InputEvent.ts
@@ -6,10 +6,10 @@ import IInputEventInit from './IInputEventInit.js';
  *
  */
 export default class InputEvent extends UIEvent {
-	public readonly data: string = '';
-	public readonly dataTransfer: DataTransfer = null;
-	public readonly inputType: string = '';
-	public readonly isComposing: boolean = false;
+	public readonly data: string;
+	public readonly dataTransfer: DataTransfer;
+	public readonly inputType: string;
+	public readonly isComposing: boolean;
 
 	/**
 	 * Constructor.
@@ -17,14 +17,12 @@ export default class InputEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IInputEventInit = null) {
+	constructor(type: string, eventInit: IInputEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.data = eventInit.data || '';
-			this.dataTransfer = eventInit.dataTransfer || null;
-			this.inputType = eventInit.inputType || '';
-			this.isComposing = eventInit.isComposing || false;
-		}
+		this.data = eventInit?.data ?? '';
+		this.dataTransfer = eventInit?.dataTransfer ?? null;
+		this.inputType = eventInit?.inputType ?? '';
+		this.isComposing = eventInit?.isComposing ?? false;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/KeyboardEvent.ts b/packages/happy-dom/src/event/events/KeyboardEvent.ts
index 6ff36a762..632c60f1a 100644
--- a/packages/happy-dom/src/event/events/KeyboardEvent.ts
+++ b/packages/happy-dom/src/event/events/KeyboardEvent.ts
@@ -9,15 +9,15 @@ export default class KeyboardEvent extends UIEvent {
 	public static DOM_KEY_LOCATION_LEFT = 1;
 	public static DOM_KEY_LOCATION_RIGHT = 2;
 	public static DOM_KEY_LOCATION_NUMPAD = 3;
-	public readonly altKey: boolean = false;
-	public readonly code: string = '';
-	public readonly ctrlKey: boolean = false;
-	public readonly isComposing: boolean = false;
-	public readonly key: string = '';
-	public readonly location: number = 0;
-	public readonly metaKey: boolean = false;
-	public readonly repeat: boolean = false;
-	public readonly shiftKey: boolean = false;
+	public readonly altKey: boolean;
+	public readonly code: string;
+	public readonly ctrlKey: boolean;
+	public readonly isComposing: boolean;
+	public readonly key: string;
+	public readonly location: number;
+	public readonly metaKey: boolean;
+	public readonly repeat: boolean;
+	public readonly shiftKey: boolean;
 
 	/**
 	 * Constructor.
@@ -25,19 +25,17 @@ export default class KeyboardEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IKeyboardEventInit = null) {
+	constructor(type: string, eventInit: IKeyboardEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.altKey = eventInit.altKey || false;
-			this.code = eventInit.code || '';
-			this.ctrlKey = eventInit.ctrlKey || false;
-			this.isComposing = eventInit.isComposing || false;
-			this.key = eventInit.key || '';
-			this.location = eventInit.location !== undefined ? eventInit.location : 0;
-			this.metaKey = eventInit.metaKey || false;
-			this.repeat = eventInit.repeat || false;
-			this.shiftKey = eventInit.shiftKey || false;
-		}
+		this.altKey = eventInit?.altKey ?? false;
+		this.code = eventInit?.code ?? '';
+		this.ctrlKey = eventInit?.ctrlKey ?? false;
+		this.isComposing = eventInit?.isComposing ?? false;
+		this.key = eventInit?.key ?? '';
+		this.location = eventInit?.location ?? 0;
+		this.metaKey = eventInit?.metaKey ?? false;
+		this.repeat = eventInit?.repeat ?? false;
+		this.shiftKey = eventInit?.shiftKey ?? false;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/MediaQueryListEvent.ts b/packages/happy-dom/src/event/events/MediaQueryListEvent.ts
index 9125568e8..9d9f9e9eb 100644
--- a/packages/happy-dom/src/event/events/MediaQueryListEvent.ts
+++ b/packages/happy-dom/src/event/events/MediaQueryListEvent.ts
@@ -5,8 +5,8 @@ import IMediaQueryListInit from './IMediaQueryListInit.js';
  *
  */
 export default class MediaQueryListEvent extends Event {
-	public readonly matches: boolean = false;
-	public readonly media: string = '';
+	public readonly matches: boolean;
+	public readonly media: string;
 
 	/**
 	 * Constructor.
@@ -14,12 +14,10 @@ export default class MediaQueryListEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IMediaQueryListInit = null) {
+	constructor(type: string, eventInit: IMediaQueryListInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.matches = eventInit.matches || false;
-			this.media = eventInit.media || '';
-		}
+		this.matches = eventInit?.matches ?? false;
+		this.media = eventInit?.media ?? '';
 	}
 }
diff --git a/packages/happy-dom/src/event/events/MessageEvent.ts b/packages/happy-dom/src/event/events/MessageEvent.ts
index a0b2260cf..a2cd12f8e 100644
--- a/packages/happy-dom/src/event/events/MessageEvent.ts
+++ b/packages/happy-dom/src/event/events/MessageEvent.ts
@@ -9,11 +9,11 @@ import IMessageEventInit from './IMessageEventInit.js';
  * @see https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent
  */
 export default class MessageEvent extends Event {
-	public data?: unknown | null = null;
-	public origin?: string = '';
-	public lastEventId?: string = '';
-	public source?: IWindow | null = null;
-	public ports?: IMessagePort[] = [];
+	public readonly data: unknown | null;
+	public readonly origin: string;
+	public readonly lastEventId: string;
+	public readonly source: IWindow | null;
+	public readonly ports: IMessagePort[];
 
 	/**
 	 * Constructor.
@@ -21,12 +21,13 @@ export default class MessageEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit?: IMessageEventInit) {
+	constructor(type: string, eventInit: IMessageEventInit | null = null) {
 		super(type, eventInit);
-		this.data = eventInit?.data !== undefined ? eventInit.data : null;
-		this.origin = eventInit?.origin || '';
-		this.lastEventId = eventInit?.lastEventId || '';
-		this.source = eventInit?.source || null;
-		this.ports = eventInit?.ports || [];
+
+		this.data = eventInit?.data ?? null;
+		this.origin = eventInit?.origin ?? '';
+		this.lastEventId = eventInit?.lastEventId ?? '';
+		this.source = eventInit?.source ?? null;
+		this.ports = eventInit?.ports ?? [];
 	}
 }
diff --git a/packages/happy-dom/src/event/events/MouseEvent.ts b/packages/happy-dom/src/event/events/MouseEvent.ts
index 88dd6f04b..036a902a9 100644
--- a/packages/happy-dom/src/event/events/MouseEvent.ts
+++ b/packages/happy-dom/src/event/events/MouseEvent.ts
@@ -6,22 +6,22 @@ import IMouseEventInit from './IMouseEventInit.js';
  *
  */
 export default class MouseEvent extends UIEvent {
-	public readonly altKey: boolean = false;
-	public readonly button: number = 0;
-	public readonly buttons: number = 0;
-	public readonly clientX: number = 0;
-	public readonly clientY: number = 0;
-	public readonly ctrlKey: boolean = false;
-	public readonly metaKey: boolean = false;
-	public readonly movementX: number = 0;
-	public readonly movementY: number = 0;
-	public readonly offsetX: number = 0;
-	public readonly offsetY: number = 0;
-	public readonly region: string = '';
-	public readonly relatedTarget: EventTarget = null;
-	public readonly screenX: number = 0;
-	public readonly screenY: number = 0;
-	public readonly shiftKey: boolean = false;
+	public readonly altKey: boolean;
+	public readonly button: number;
+	public readonly buttons: number;
+	public readonly clientX: number;
+	public readonly clientY: number;
+	public readonly ctrlKey: boolean;
+	public readonly metaKey: boolean;
+	public readonly movementX: number;
+	public readonly movementY: number;
+	public readonly offsetX: number;
+	public readonly offsetY: number;
+	public readonly region: string;
+	public readonly relatedTarget: EventTarget | null;
+	public readonly screenX: number;
+	public readonly screenY: number;
+	public readonly shiftKey: boolean;
 
 	/**
 	 * Constructor.
@@ -29,24 +29,22 @@ export default class MouseEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IMouseEventInit = null) {
+	constructor(type: string, eventInit: IMouseEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.altKey = eventInit.altKey || false;
-			this.button = eventInit.button !== undefined ? eventInit.button : 0;
-			this.buttons = eventInit.buttons !== undefined ? eventInit.buttons : 0;
-			this.clientX = eventInit.clientX !== undefined ? eventInit.clientX : 0;
-			this.clientY = eventInit.clientY !== undefined ? eventInit.clientY : 0;
-			this.ctrlKey = eventInit.ctrlKey || false;
-			this.metaKey = eventInit.metaKey || false;
-			this.movementX = eventInit.movementX || 0;
-			this.movementY = eventInit.movementY || 0;
-			this.region = eventInit.region || '';
-			this.relatedTarget = eventInit.relatedTarget || null;
-			this.screenX = eventInit.screenX !== undefined ? eventInit.screenX : 0;
-			this.screenY = eventInit.screenY !== undefined ? eventInit.screenY : 0;
-			this.shiftKey = eventInit.shiftKey || false;
-		}
+		this.altKey = eventInit?.altKey ?? false;
+		this.button = eventInit?.button ?? 0;
+		this.buttons = eventInit?.buttons ?? 0;
+		this.clientX = eventInit?.clientX ?? 0;
+		this.clientY = eventInit?.clientY ?? 0;
+		this.ctrlKey = eventInit?.ctrlKey ?? false;
+		this.metaKey = eventInit?.metaKey ?? false;
+		this.movementX = eventInit?.movementX ?? 0;
+		this.movementY = eventInit?.movementY ?? 0;
+		this.region = eventInit?.region ?? '';
+		this.relatedTarget = eventInit?.relatedTarget ?? null;
+		this.screenX = eventInit?.screenX ?? 0;
+		this.screenY = eventInit?.screenY ?? 0;
+		this.shiftKey = eventInit?.shiftKey ?? false;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/PointerEvent.ts b/packages/happy-dom/src/event/events/PointerEvent.ts
index bd0cc4ae0..32aa9d805 100644
--- a/packages/happy-dom/src/event/events/PointerEvent.ts
+++ b/packages/happy-dom/src/event/events/PointerEvent.ts
@@ -5,16 +5,20 @@ import IPointerEventInit from './IPointerEventInit.js';
  *
  */
 export default class PointerEvent extends MouseEvent {
-	public readonly pointerId: number = 0;
-	public readonly width: number = 0;
-	public readonly height: number = 0;
-	public readonly pressure: number = 0;
-	public readonly tangentialPressure: number = 0;
-	public readonly tiltX: number = 0;
-	public readonly tiltY: number = 0;
-	public readonly twist: number = 0;
-	public readonly pointerType: string = '';
-	public readonly isPrimary: boolean = false;
+	public readonly pointerId: number;
+	public readonly width: number;
+	public readonly height: number;
+	public readonly pressure: number;
+	public readonly tangentialPressure: number;
+	public readonly tiltX: number;
+	public readonly tiltY: number;
+	public readonly twist: number;
+	public readonly altitudeAngle: number;
+	public readonly azimuthAngle: number;
+	public readonly pointerType: string;
+	public readonly isPrimary: boolean;
+	public readonly coalescedEvents: PointerEvent[];
+	public readonly predictedEvents: PointerEvent[];
 
 	/**
 	 * Constructor.
@@ -22,21 +26,26 @@ export default class PointerEvent extends MouseEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IPointerEventInit = null) {
+	constructor(type: string, eventInit: IPointerEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.pointerId = eventInit.pointerId !== undefined ? eventInit.pointerId : 0;
-			this.width = eventInit.width !== undefined ? eventInit.width : 0;
-			this.height = eventInit.height !== undefined ? eventInit.height : 0;
-			this.pressure = eventInit.pressure !== undefined ? eventInit.pressure : 0;
-			this.tangentialPressure =
-				eventInit.tangentialPressure !== undefined ? eventInit.tangentialPressure : 0;
-			this.tiltX = eventInit.tiltX !== undefined ? eventInit.tiltX : 0;
-			this.tiltY = eventInit.tiltY !== undefined ? eventInit.tiltY : 0;
-			this.twist = eventInit.twist !== undefined ? eventInit.twist : 0;
-			this.pointerType = eventInit.pointerType !== undefined ? eventInit.pointerType : '';
-			this.isPrimary = eventInit.isPrimary || eventInit.isPrimary;
-		}
+		this.pointerId = eventInit?.pointerId ?? 0;
+		this.width = eventInit?.width ?? 1;
+		this.height = eventInit?.height ?? 1;
+		this.pressure = eventInit?.pressure ?? 0;
+		this.tangentialPressure = eventInit?.tangentialPressure ?? 0;
+		this.tiltX = eventInit?.tiltX ?? 0;
+		this.tiltY = eventInit?.tiltY ?? 0;
+		this.twist = eventInit?.twist ?? 0;
+		this.altitudeAngle = eventInit?.altitudeAngle ?? 0;
+		this.azimuthAngle = eventInit?.azimuthAngle ?? 0;
+		this.pointerType = eventInit?.pointerType ?? '';
+		this.isPrimary = eventInit?.isPrimary ?? false;
+		this.coalescedEvents = eventInit?.coalescedEvents ?? [];
+		this.predictedEvents = eventInit?.predictedEvents ?? [];
 	}
+
+	public getCoalescedEvents = (): PointerEvent[] => this.coalescedEvents;
+
+	public getPredictedEvents = (): PointerEvent[] => this.predictedEvents;
 }
diff --git a/packages/happy-dom/src/event/events/ProgressEvent.ts b/packages/happy-dom/src/event/events/ProgressEvent.ts
index 071e26f8d..1ed8dd6da 100644
--- a/packages/happy-dom/src/event/events/ProgressEvent.ts
+++ b/packages/happy-dom/src/event/events/ProgressEvent.ts
@@ -5,9 +5,9 @@ import IProgressEventInit from './IProgressEventInit.js';
  *
  */
 export default class ProgressEvent extends Event {
-	public readonly lengthComputable: boolean = false;
-	public readonly loaded: number = 0;
-	public readonly total: number = 0;
+	public readonly lengthComputable: boolean;
+	public readonly loaded: number;
+	public readonly total: number;
 
 	/**
 	 * Constructor.
@@ -15,13 +15,11 @@ export default class ProgressEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IProgressEventInit = null) {
+	constructor(type: string, eventInit: IProgressEventInit | null = null) {
 		super(type);
 
-		if (eventInit) {
-			this.lengthComputable = eventInit.lengthComputable || false;
-			this.loaded = eventInit.loaded !== undefined ? eventInit.loaded : 0;
-			this.total = eventInit.total !== undefined ? eventInit.total : 0;
-		}
+		this.lengthComputable = eventInit?.lengthComputable ?? false;
+		this.loaded = eventInit?.loaded ?? 0;
+		this.total = eventInit?.total ?? 0;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/StorageEvent.ts b/packages/happy-dom/src/event/events/StorageEvent.ts
index a824409fe..24ea5498c 100644
--- a/packages/happy-dom/src/event/events/StorageEvent.ts
+++ b/packages/happy-dom/src/event/events/StorageEvent.ts
@@ -6,10 +6,11 @@ import Storage from '../../storage/Storage.js';
  *
  */
 export default class StorageEvent extends Event {
-	public readonly key: string = null;
-	public readonly newValue: string = null;
-	public readonly oldValue: string = null;
-	public readonly storageArea: Storage = null;
+	public readonly key: string | null;
+	public readonly oldValue: string | null;
+	public readonly newValue: string | null;
+	public readonly url: string;
+	public readonly storageArea: Storage | null;
 
 	/**
 	 * Constructor.
@@ -17,14 +18,13 @@ export default class StorageEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IStorageEventInit = null) {
+	constructor(type: string, eventInit: IStorageEventInit | null = null) {
 		super(type);
 
-		if (eventInit) {
-			this.key = eventInit.key !== undefined ? eventInit.key : null;
-			this.newValue = eventInit.newValue !== undefined ? eventInit.newValue : null;
-			this.oldValue = eventInit.oldValue !== undefined ? eventInit.oldValue : null;
-			this.storageArea = eventInit.storageArea !== undefined ? eventInit.storageArea : null;
-		}
+		this.key = eventInit?.key ?? null;
+		this.oldValue = eventInit?.oldValue ?? null;
+		this.newValue = eventInit?.newValue ?? null;
+		this.url = eventInit?.url ?? '';
+		this.storageArea = eventInit?.storageArea ?? null;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/SubmitEvent.ts b/packages/happy-dom/src/event/events/SubmitEvent.ts
index 773ace36e..864173cf1 100644
--- a/packages/happy-dom/src/event/events/SubmitEvent.ts
+++ b/packages/happy-dom/src/event/events/SubmitEvent.ts
@@ -6,7 +6,7 @@ import IHTMLElement from '../../nodes/html-element/IHTMLElement.js';
  * An event triggered by form submit buttons.
  */
 export default class SubmitEvent extends Event {
-	public readonly submitter: IHTMLElement;
+	public readonly submitter: IHTMLElement | null;
 
 	/**
 	 * Constructor.
@@ -14,9 +14,9 @@ export default class SubmitEvent extends Event {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: ISubmitEventInit = null) {
+	constructor(type: string, eventInit: ISubmitEventInit | null = null) {
 		super(type, eventInit);
 
-		this.submitter = eventInit?.submitter || null;
+		this.submitter = eventInit?.submitter ?? null;
 	}
 }
diff --git a/packages/happy-dom/src/event/events/WheelEvent.ts b/packages/happy-dom/src/event/events/WheelEvent.ts
index 3cfaa82ac..097d06007 100644
--- a/packages/happy-dom/src/event/events/WheelEvent.ts
+++ b/packages/happy-dom/src/event/events/WheelEvent.ts
@@ -8,10 +8,10 @@ export default class WheelEvent extends UIEvent {
 	public static DOM_DELTA_PIXEL = 0;
 	public static DOM_DELTA_LINE = 1;
 	public static DOM_DELTA_PAGE = 2;
-	public readonly deltaX: number = 0;
-	public readonly deltaY: number = 0;
-	public readonly deltaZ: number = 0;
-	public readonly deltaMode: number = 0;
+	public readonly deltaX: number;
+	public readonly deltaY: number;
+	public readonly deltaZ: number;
+	public readonly deltaMode: number;
 
 	/**
 	 * Constructor.
@@ -19,14 +19,12 @@ export default class WheelEvent extends UIEvent {
 	 * @param type Event type.
 	 * @param [eventInit] Event init.
 	 */
-	constructor(type: string, eventInit: IWheelEventInit = null) {
+	constructor(type: string, eventInit: IWheelEventInit | null = null) {
 		super(type, eventInit);
 
-		if (eventInit) {
-			this.deltaX = eventInit.deltaX !== undefined ? eventInit.deltaX : 0;
-			this.deltaY = eventInit.deltaY !== undefined ? eventInit.deltaY : 0;
-			this.deltaZ = eventInit.deltaZ !== undefined ? eventInit.deltaZ : 0;
-			this.deltaMode = eventInit.deltaMode !== undefined ? eventInit.deltaMode : 0;
-		}
+		this.deltaX = eventInit?.deltaX ?? 0;
+		this.deltaY = eventInit?.deltaY ?? 0;
+		this.deltaZ = eventInit?.deltaZ ?? 0;
+		this.deltaMode = eventInit?.deltaMode ?? 0;
 	}
 }
diff --git a/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts b/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts
index 054fa16c2..fb5194e66 100644
--- a/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts
+++ b/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts
@@ -394,6 +394,8 @@ describe('HTMLElement', () => {
 			expect((<PointerEvent>(<unknown>triggeredEvent)).composed).toBe(true);
 			expect((<PointerEvent>(<unknown>triggeredEvent)).target === element).toBe(true);
 			expect((<PointerEvent>(<unknown>triggeredEvent)).currentTarget === element).toBe(true);
+			expect((<PointerEvent>(<unknown>triggeredEvent)).width).toBe(1);
+			expect((<PointerEvent>(<unknown>triggeredEvent)).height).toBe(1);
 		});
 	});