1class APIPerformanceMonitor {
2    constructor(windowSize = 300000) { // 5 minutes in milliseconds
3        this.measurements = new Map();
4        this.windowSize = windowSize;
5    }
6
7    recordResponse(timestamp, duration) {
8        this.measurements.set(timestamp, duration);
9        this.cleanup(timestamp);
10    }
11
12    cleanup(currentTime) {
13        const threshold = currentTime - this.windowSize;
14        for (let [timestamp] of this.measurements) {
15            if (timestamp < threshold) {
16                this.measurements.delete(timestamp);
17            }
18        }
19    }
20
21    calculateAverageResponse(currentTime) {
22        this.cleanup(currentTime);
23        if (this.measurements.size === 0) return 0;
24        
25        const sum = Array.from(this.measurements.values())
26            .reduce((acc, val) => acc + val, 0);
27        return Math.round(sum / this.measurements.size);
28    }
29}
30
31const monitor = new APIPerformanceMonitor();
32const baseTime = Date.now();
33
34monitor.recordResponse(baseTime - 360000, 150);  // 6 minutes ago
35monitor.recordResponse(baseTime - 240000, 200);  // 4 minutes ago
36monitor.recordResponse(baseTime - 120000, 300);  // 2 minutes ago
37monitor.recordResponse(baseTime - 60000, 250);   // 1 minute ago
38monitor.recordResponse(baseTime, 100);           // now
39
40console.log(monitor.calculateAverageResponse(baseTime));