chore: re-add event types and cleanup

packages/core/application/application-common.ts

@@ -2,7 +2,6 @@ import { initAccessibilityCssHelper } from '../accessibility/accessibility-css-h
 import { initAccessibilityFontScale } from '../accessibility/font-scale';
 import { CoreTypes } from '../core-types';
 import { CSSUtils } from '../css/system-classes';
-import { Observable } from '../data/observable';
 import { Device } from '../platform';
 import { profile } from '../profiling';
 import { Trace } from '../trace';
@@ -20,11 +19,13 @@ import {
 	ApplicationEventData,
 	CssChangedEventData,
 	DiscardedErrorEventData,
+	FontScaleChangedEventData,
 	LaunchEventData,
 	LoadAppCSSEventData,
 	NativeScriptError,
 	OrientationChangedEventData,
 	SystemAppearanceChangedEventData,
+	UnhandledErrorEventData,
 } from './application-interfaces';
 
 const ORIENTATION_CSS_CLASSES = [
@@ -38,7 +39,21 @@ const SYSTEM_APPEARANCE_CSS_CLASSES = [
 	`${CSSUtils.CLASS_PREFIX}${CoreTypes.SystemAppearance.dark}`,
 ];
 
-export class ApplicationCommon extends Observable {
+const globalEvents = global.NativeScriptGlobals.events;
+
+// helper interface to correctly type Application event handlers
+interface ApplicationEvents {
+	on(
+		eventNames: string,
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+	off(eventNames: string, callback?: any, thisArg?: any): void;
+	notify<T = ApplicationEventData>(eventData: T): void;
+	hasListeners(eventName: string): boolean;
+}
+
+export class ApplicationCommon {
 	readonly launchEvent = 'launch';
 	readonly suspendEvent = 'suspend';
 	readonly displayedEvent = 'displayed';
@@ -54,9 +69,14 @@ export class ApplicationCommon extends Observable {
 	readonly fontScaleChangedEvent = 'fontScaleChanged';
 	readonly livesyncEvent = 'livesync';
 
-	constructor() {
-		super();
+	// Application events go through the global events.
+	readonly on: ApplicationEvents['on'] = globalEvents.on.bind(globalEvents);
+	readonly off: ApplicationEvents['off'] = globalEvents.off.bind(globalEvents);
+	readonly notify: ApplicationEvents['notify'] = globalEvents.notify.bind(globalEvents);
+	readonly hasListeners: ApplicationEvents['hasListeners'] =
+		globalEvents.hasListeners.bind(globalEvents);
 
+	constructor() {
 		global.NativeScriptGlobals.appInstanceReady = true;
 
 		global.__onUncaughtError = (error: NativeScriptError) => {
@@ -345,15 +365,6 @@ export class ApplicationCommon extends Observable {
 		}
 	}
 
-	on = global.NativeScriptGlobals.events.on.bind(global.NativeScriptGlobals.events);
-	off = global.NativeScriptGlobals.events.off.bind(global.NativeScriptGlobals.events);
-	notify = global.NativeScriptGlobals.events.notify.bind(
-		global.NativeScriptGlobals.events
-	);
-	hasListeners = global.NativeScriptGlobals.events.hasListeners.bind(
-		global.NativeScriptGlobals.events
-	);
-
 	run(entry?: string | NavigationEntry) {
 		throw new Error('run() Not implemented.');
 	}
@@ -531,6 +542,3 @@ export class ApplicationCommon extends Observable {
 		return this.ios;
 	}
 }
-
-// export const AndroidApplication: IAndroidApplication = undefined;
-// export const iOSApplication: IiOSApplication = undefined;

packages/core/application/application-interfaces.ts

@@ -1,6 +1,6 @@
 // Types
-import type { AndroidApplication, iOSApplication, ApplicationCommon } from '.';
-import type { EventData } from '../data/observable';
+import type { ApplicationCommon } from '.';
+import type { EventData, Observable } from '../data/observable';
 import type { View } from '../ui/core/view';
 
 /**
@@ -16,7 +16,12 @@ export interface NativeScriptError extends Error {
 /**
  * Event data containing information for the application events.
  */
-export interface ApplicationEventData extends EventData {
+export interface ApplicationEventData {
+	/**
+	 * The name of the event.
+	 */
+	eventName: string;
+
 	/**
 	 * Gets the native iOS event arguments. Valid only when running on iOS.
 	 */
@@ -30,7 +35,7 @@ export interface ApplicationEventData extends EventData {
 	/**
 	 * The instance that has raised the event.
 	 */
-	object: ApplicationCommon;
+	object: ApplicationCommon | Observable;
 }
 
 /**

packages/core/application/application.d.ts

@@ -3,7 +3,128 @@
 export * from './application-common';
 export * from './application-interfaces';
 
-export const Application: ApplicationCommon;
+export const Application: ApplicationCommon & ApplicationCommonEvents;
+
+export interface ApplicationCommonEvents {
+	/**
+	 * This event is raised when application css is changed.
+	 */
+	on(
+		event: 'cssChanged',
+		callback: (args: CssChangedEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * Event raised then livesync operation is performed.
+	 */
+	on(
+		event: 'livesync',
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when application css is changed.
+	 */
+	on(
+		event: 'cssChanged',
+		callback: (args: CssChangedEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised on application launchEvent.
+	 */
+	on(event: 'launch', callback: (args: LaunchEventData) => void, thisArg?: any): void;
+
+	/**
+	 * This event is raised after the application has performed most of its startup actions.
+	 * Its intent is to be suitable for measuring app startup times.
+	 * @experimental
+	 */
+	on(
+		event: 'displayed',
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when the Application is suspended.
+	 */
+	on(
+		event: 'suspend',
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when the Application is resumed after it has been suspended.
+	 */
+	on(
+		event: 'resume',
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when the Application is about to exit.
+	 */
+	on(event: 'exit', callback: (args: ApplicationEventData) => void, thisArg?: any): void;
+
+	/**
+	 * This event is raised when there is low memory on the target device.
+	 */
+	on(
+		event: 'lowMemory',
+		callback: (args: ApplicationEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when an uncaught error occurs while the application is running.
+	 */
+	on(
+		event: 'uncaughtError',
+		callback: (args: UnhandledErrorEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when an discarded error occurs while the application is running.
+	 */
+	on(
+		event: 'discardedError',
+		callback: (args: DiscardedErrorEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when the orientation of the application changes.
+	 */
+	on(
+		event: 'orientationChanged',
+		callback: (args: OrientationChangedEventData) => void,
+		thisArg?: any
+	): void;
+
+	/**
+	 * This event is raised when the operating system appearance changes
+	 * between light and dark theme (for Android);
+	 * between light and dark mode (for iOS) and vice versa.
+	 */
+	on(
+		event: 'systemAppearanceChanged',
+		callback: (args: SystemAppearanceChangedEventData) => void,
+		thisArg?: any
+	): void;
+
+	on(
+		event: 'fontScaleChanged',
+		callback: (args: FontScaleChangedEventData) => void,
+		thisArg?: any
+	): void;
+}
 
 export interface AndroidApplication extends ApplicationCommon {
 	readonly activityCreatedEvent;
@@ -36,6 +157,62 @@ export interface AndroidApplication extends ApplicationCommon {
 		) => void
 	): void;
 	unregisterBroadcastReceiver(intentFilter: string): void;
+
+	on(
+		event: 'activityCreated',
+		callback: (args: AndroidActivityBundleEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityDestroyed',
+		callback: (args: AndroidActivityEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityStarted',
+		callback: (args: AndroidActivityEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityPaused',
+		callback: (args: AndroidActivityEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityResumed',
+		callback: (args: AndroidActivityEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityStopped',
+		callback: (args: AndroidActivityEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'saveActivityState',
+		callback: (args: AndroidActivityBundleEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityResult',
+		callback: (args: AndroidActivityResultEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityBackPressed',
+		callback: (args: AndroidActivityBackPressedEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityNewIntent',
+		callback: (args: AndroidActivityNewIntentEventData) => void,
+		thisArg?: any
+	): void;
+	on(
+		event: 'activityRequestPermissions',
+		callback: (args: AndroidActivityRequestPermissionsEventData) => void,
+		thisArg?: any
+	): void;
 }
 
 export interface iOSApplication extends ApplicationCommon {