1export default class EventAggregator {
 2  constructor() {
 3    this.subscriptions = { };
 4  }
 5
 6  subscribe(event, subscriber) {
 7    this._subscriptionsFor(event).add(subscriber);
 8  }
 9
10  publish(event) {
11    this._subscriptionsFor(event.event).forEach((x) => {
12      x.notify(event);
13    });
14  }
15
16  unsubscribe(subscriber) {
17    for (var subscription in this.subscriptions) {
18      let subscribers = this._subscriptionsFor(subscription)
19      if (subscribers.has(subscriber)) {
20        subscribers.delete(subscriber);
21      }
22    }
23  }
24
25  _subscriptionsFor(event) {
26    let key = event;
27    if (!this.subscriptions.hasOwnProperty(key)) {
28      this.subscriptions[key] = new Set();
29    }
30    return this.subscriptions[key];
31  }
32}