1class TimeSeriesProcessor {
2    static #SMOOTHING_FACTOR = 0.15;
3
4    static movingAverage(values, windowSize) {
5        const result = [];
6        for (let i = 0; i < values.length; i++) {
7            let sum = 0;
8            let count = 0;
9            for (let j = Math.max(0, i - windowSize + 1); j <= i; j++) {
10                sum += values[j];
11                count++;
12            }
13            result.push(Number((sum / count).toFixed(2)));
14        }
15        return result;
16    }
17
18    static exponentialSmoothing(values) {
19        const result = [values[0]];
20        for (let i = 1; i < values.length; i++) {
21            const smoothed = this.#SMOOTHING_FACTOR * values[i] + 
22                           (1 - this.#SMOOTHING_FACTOR) * result[i - 1];
23            result.push(Number(smoothed.toFixed(2)));
24        }
25        return result;
26    }
27
28    static process(data, windowSize = 3) {
29        const movingAvg = this.movingAverage(data, windowSize);
30        return this.exponentialSmoothing(movingAvg);
31    }
32}
33
34const data = [10, 15, 12, 18, 20];
35console.log(TimeSeriesProcessor.process(data));