class Storage {
    constructor(capacity) {
        this.capacity = capacity;
        this.storage = [];
    }

    get totalCost() {
        return  this.storage.reduce((acc, curr) => acc + curr.price * curr.quantity, 0);
    }

    addProduct(product) {
       this.storage.push(product);
       this.capacity -= product.quantity;
    }

    getProducts() {
        let outputJSON = [];
       this.storage.forEach(prod => {
            outputJSON.push(JSON.stringify(prod));
        });
        return outputJSON.join('\n');
    }

}