1class PromotionCalculator {
2    #promotions = new Map();
3
4    addPromotion(code, calculation) {
5        this.#promotions.set(code.toUpperCase(), calculation);
6    }
7
8    calculateTotal(basePrice, ...promoCodes) {
9        let finalPrice = basePrice;
10        
11        // Sort promo codes to ensure consistent application order
12        const sortedCodes = [...new Set(promoCodes)].sort();
13        
14        for (const code of sortedCodes) {
15            const promotion = this.#promotions.get(code.toUpperCase());
16            if (promotion) {
17                finalPrice = promotion(finalPrice);
18            }
19        }
20
21        return Number(finalPrice.toFixed(2));
22    }
23}
24
25const calculator = new PromotionCalculator();
26
27// 10% off
28calculator.addPromotion('SAVE10', price => price * 0.9);
29
30// Fixed $20 off
31calculator.addPromotion('MINUS20', price => Math.max(0, price - 20));
32
33// Additional 5% off
34calculator.addPromotion('EXTRA5', price => price * 0.95);
35
36const cartPrice = 100;
37console.log(calculator.calculateTotal(
38    cartPrice,
39    'SAVE10',
40    'MINUS20',
41    'EXTRA5'
42));