Observer Pattern TS

observer.ts

interface IPublisher {
	subscribe(observer: Observer): void
	unsubscribe(observer: Observer): void
	notify(news: String): void
}

interface IObserver {
	update(news: string): void
}

class MoonsNews implements IPublisher {

	private observers: Observer[] = [];

	subscribe(observer: Observer) {
		this.observers.push(observer);
	}
	
	unsubscribe(observer: Observer) {
		this.observers = this.observers.filter(obs => obs !== observer);
	}
	
	notify(news: string) {
		this.observers.forEach(obs => obs.update(news));
	}
}

class Observer implements IObserver {
	constructor(public readonly name: string) { }
	private feed: string[] = [];
	update(news: string) {
		this.feed.push(news);
		console.log(`${this.name} recibió notificación`);
	}
	showFeed() {
		console.log(this.name + ":" + this.feed);
		return this.name + ":" + this.feed;
	}
}

const patientMX = new Observer("Carlos");
const patientCOL = new Observer("Juan Pa");

const moonsNews = new MoonsNews();

moonsNews.subscribe(patientMX);
moonsNews.subscribe(patientCOL);

moonsNews.notify("Ya hay moons hechos de nuevo material!");
console.log(patientMX.showFeed());
console.log(patientCOL.showFeed());

moonsNews.unsubscribe(patientMX);

moonsNews.notify("Los moons eliminaron a los brackets!");
console.log(patientMX.showFeed());
console.log(patientCOL.showFeed());

const patientPE = new Observer("Pablo");
moonsNews.subscribe(patientPE);
console.log(patientPE.showFeed());
moonsNews.notify("Nuevos moons de colores!");
console.log(patientPE.showFeed());