1class EventEmitter {
2    subscriptions = new Map();
3
4    subscribe(eventName, callback) {
5        if (!this.subscriptions.has(eventName)) {
6            this.subscriptions.set(eventName, new Set());
7        }
8        const subscriptions = this.subscriptions.get(eventName);
9        const callbackObj = { callback };
10        subscriptions.add(callbackObj);
11
12        return {
13            release: () => {
14                subscriptions.delete(callbackObj);
15                if (subscriptions.size === 0) {
16                    delete this.subscriptions.eventName;
17                }
18            },
19        };
20    }
21
22    emit(eventName, ...args) {
23        const subscriptions = this.subscriptions.get(eventName);
24        if (subscriptions) {
25            subscriptions.forEach((cbObj) => {
26                cbObj.callback.apply(this, args);
27            });
28        }
29    }
30}