import { EventData, Page, Observable, Frame } from '@nativescript/core'; export function navigatingTo(args: EventData) { const page = args.object; page.bindingContext = new TestPage(); } export function onNavBtnTap(args) { Frame.topmost().goBack(); } export class TestPage extends Observable { constructor() { super(); } // new line of span can be set with \n from code behind get test(): string { return '\ntest'; } }