1class EventTracker {
2    static processEvents(events) {
3        return events.reduce((summary, event) => {
4            const { type, duration } = event;
5            
6            if (!summary[type]) {
7                summary[type] = {
8                    count: 0,
9                    totalDuration: 0,
10                    avgDuration: 0
11                };
12            }
13            
14            summary[type].count++;
15            summary[type].totalDuration += duration;
16            summary[type].avgDuration = Math.round(
17                summary[type].totalDuration / summary[type].count
18            );
19            
20            return summary;
21        }, {});
22    }
23}
24
25const events = [
26    { type: 'click', duration: 100 },
27    { type: 'scroll', duration: 150 },
28    { type: 'click', duration: 200 },
29    { type: 'scroll', duration: 250 }
30];
31
32console.log(EventTracker.processEvents(events));