chore: add apps for profiling

apps/new/src/plugin-demos/properties.ts

@@ -0,0 +1,75 @@
+import { Button, EventData, Page, Switch, View, getViewById, Observable, Label, PropertyChangeData } from '@nativescript/core';
+
+export function navigatingTo(args: EventData) {
+	const page = <Page>args.object;
+
+	page.bindingContext = new DemoModel(page);
+}
+
+export class DemoModel extends Observable {
+	private readonly manualProfiling: Switch;
+	private readonly automatedProfiling: Button;
+	private readonly target: Label;
+
+	private automatedProfilingInProgress = false;
+
+	constructor(container: View) {
+		super();
+
+		this.manualProfiling = getViewById(container, 'manual-profiling') as Switch;
+		this.automatedProfiling = getViewById(container, 'automated-profiling') as Button;
+		this.target = getViewById(container, 'target') as Label;
+	}
+
+	toggleManualProfiling({ value }: PropertyChangeData): void {
+		console.log(`toggleManualProfiling changed to ${value}. manualProfiling:`, this.manualProfiling);
+		this.updateAutomatedProfilingEnabled();
+	}
+
+	runAutomatedProfiling(): void {
+		if (this.automatedProfilingInProgress) {
+			return;
+		}
+
+		console.log(`runAutomatedProfiling. automatedProfiling:`, this.automatedProfiling);
+		this.automatedProfilingInProgress = true;
+		this.updateAutomatedProfilingEnabled();
+
+		const propName = 'arbitrary-prop';
+
+		// Initialise the target property so that the first property-setting action
+		// doesn't produce an outlier result due to taking a one-off code branch.
+		this.target.setProperty(propName, -1);
+
+		const onPropertyChange = () => {
+			// No-op
+		};
+
+		this.target.addEventListener(Observable.propertyChangeEvent, onPropertyChange, null);
+
+		const time = profile(() => {
+			for (let i = 0; i < 1000000; i++) {
+				this.target.setProperty(propName, i);
+			}
+		});
+
+		this.target.removeEventListener(Observable.propertyChangeEvent, onPropertyChange, null);
+
+		console.log(`1,000,000 runs of setProperty() took ${time} ms`);
+
+		this.automatedProfilingInProgress = false;
+		this.updateAutomatedProfilingEnabled();
+	}
+
+	private updateAutomatedProfilingEnabled(): void {
+		this.automatedProfiling.isEnabled = !this.automatedProfilingInProgress && !this.manualProfiling.checked;
+	}
+}
+
+function profile(action: () => void) {
+	const start = global.isIOS ? (global as any).performance.now() : __time();
+	action();
+	const stop = global.isIOS ? (global as any).performance.now() : __time();
+
+	return stop - start;
+}