import { Observable } from '@nativescript/core' export class HelloWorldModel extends Observable { private _counter: number private _message: string constructor() { super() // Initialize default values. this._counter = 42 this.updateMessage() } get message(): string { return this._message } set message(value: string) { if (this._message !== value) { this._message = value this.notifyPropertyChange('message', value) } } onTap() { this._counter-- this.updateMessage() } private updateMessage() { if (this._counter <= 0) { this.message = 'Hoorraaay! You unlocked the NativeScript clicker achievement!' } else { this.message = `${this._counter} taps left` } } }