| export class Subscribable<TListener extends Function> { | |
| protected listeners = new Set<TListener>() | |
| constructor() { | |
| this.subscribe = this.subscribe.bind(this) | |
| } | |
| subscribe(listener: TListener): () => void { | |
| this.listeners.add(listener) | |
| this.onSubscribe() | |
| return () => { | |
| this.listeners.delete(listener) | |
| this.onUnsubscribe() | |
| } | |
| } | |
| hasListeners(): boolean { | |
| return this.listeners.size > 0 | |
| } | |
| protected onSubscribe(): void { | |
| // Do nothing | |
| } | |
| protected onUnsubscribe(): void { | |
| // Do nothing | |
| } | |
| } | |